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I am working on a 'Smart Device Project' using .Net Framework 3.5. I am trying to connect to some Java SOAP services on a remote server.
In order to do that, I added 'Web References' to my project.
When I try to call my web service I get a WebException 'Unable to connect to the remote server' with the inner exception being 'No connection could be made because the target machine actively refused it'.
I searched quite a lot on the Web and StackOverflow and found a lot of ASP configuration and 'Unavaliable port' answers, but as I have another application using the exact same Service successfully, I can't get why the new one isn't getting through (It did sometimes through my tests so I suppose my client implementation isn't that bad)
I tried to look if there was some connection issue on the port by using some TcpClient:
System.Net.Sockets.TcpClient client = new System.Net.Sockets.TcpClient();
try
{
client.Connect("myServerName", 8087);
MessageBox.Show("Success");
} catch (Exception ex)
{
MessageBox.Show("Failure");
}
finally
{
client.Close();
}
This connection succeed.
Here is a sample on how I call my WebService:
WSServiceExtended srv = new WSServiceExtended();
srv.Proxy = new System.Net.WebProxy();
ServeurWSI wsi = new ServeurWSI();
srv.Url = "http://myServerName:8087/myServerApp/services/myService";
wsr = srv.login(wsi);
The service is called 'Extended' because I overrided the auto-generated one in order to add Cookie managment since I am using the Compact Framework. Following the sample in this thread:
https://social.msdn.microsoft.com/Forums/en-US/34d88228-0b68-4fda-a8cd-58efe6b47958/no-cookies-sessionstate-in-compact-framework?forum=vssmartdevicesvbcs
EDIT:
I made some new tests with the Web references and got it to work.
When I add the Web Reference, I have to put some Url to the Web Service. When I set it with the actual hostname instead of the 'localhost' everything is fine.
But then, since I set it manually to the real address just before the call, it shouldn't matter
srv.Url = "http://myServerName:8087/myServerApp/services/myService";
EDIT2:
I might have forgotten some specifics about my environnement.
The Web Services are exposed on my computer on some Tomcat Server.
The application I am working on is also developped on this computer (That's why I can add Web References by putting 'localhost' in the address)
The application is then deployed on a distant device (Windows CE) that will make calls the Web Services through WIFI (There, localhost wouldn't work then)
I tried calling the Web services from other computers successfully.
I'm beginning to think that there might be some differential between the called Url and the one that is set, otherwise, how would I have a difference in behaviour such as the one described in the first edit?
EDIT3:
Well..Seems like it's not a network issue but a .Net compact framework (usage?) issue...
The Url property of the Web Service implementation is simply ignored and the one in the Reference.cs is used in place.
If someone had some idea on how I could troubleshot this, I would really appreciate it.
That error means that you reached a server and the server said "no way". So you're either hitting the wrong server or the wrong port.
I find the telnet client is useful for testing stuff like this. From the command line, you can do:
telnet [servername] [port]
So something like:
telnet myServerName 8087
If it goes to a blank screen, then it connected successfully. If it does not connect, it'll tell you.
The telnet client is no longer installed by default in Windows 7+, so you'll have to install it. See here for instructions: https://technet.microsoft.com/en-ca/library/cc771275
If the connection does open, you could paste in an actual HTTP request to see what happens. A simple GET would look something like this:
GET /myServerApp/services/myService HTTP/1.1
Host: myServerName:8087
One reason for this error can be that the service binds to only a certain IP address. It could well be that the service only listens on the IP that is assigned to the host name, but not on the localhost IP (127.0.0.1).
For example:
If the host myServerName has the public IP 192.168.0.1, your service can choose to listen on all IPs assigned to the host (sometimes specifying 0.0.0.0), or it can specifically listen on 192.168.0.1 only. In that case you will not be able to connect through 127.0.0.1, because the service simply doesn't listen on that IP.
You can "use" this inverse of this feature to make a service accessible only to local clients, not on the public IP-Address, by listening on 127.0.0.1 only, but not on the public IP. This is sometimes used on Linux for example to make MySQL only accessible on the host itself.
I was starting to forget this post but I finally found the problem that was messing things up and it has nothing to do with programmation.
I was doing the calls while the device was connected to the computer via the 'Windows Mobile Device Center' allowing to access the device from Windows.
While connected, the host provided is ignored and all calls on the specified port are handled by the connected computer.
Disconnecting the device allows to communicate properly...
I have a Winforms appplication written in C# that consumes web services from a Windows 2008 IIS Coldfusion server. All the web service calls succeed but one, which fails about 50% of the time with the following error:
System.InvalidOperationException was unhandled by user code
Message=There is an error in XML document (1254, 7).
with an inner exception of:
InnerException: System.IO.IOException
Message=Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host.
I checked my IIS logs and I get a 503 error (Service Unavailable) and an IIS code of 64 (The specified network is no longer available). Any suggestions would be great.
I run my web service in SOAP UI and I get the following error:
javax.net.ssl.SSLException: Connection has been shutdown: javax.net.ssl.SSLException: java.net.SocketException: Connection reset
This code works fine at one company but this error pops up almost every time for this company I'm currently working with.
I'm not sure this is applicable to the OP's specific situation, but this may help others who arrive here nowadays. One potential cause for this exception involves mismatched security protocols. If the server you're calling requires TLS 1.2 and you're using an older version of ASP.net (<= Version 4.0) you will be using an older security protocol to make your calls unless you change it. You can force ASP.net to use TLS 1.2 (shown below). This can be done anywhere in the application, but I put it just before the line that calls the web service requiring TLS 1.2:
using System.Net;
...
//Enable TLS 1.2
ServicePointManager.SecurityProtocol = (SecurityProtocolType)3072;
// Call the Web Service that requires TLS 1.2
I recently got a similar message when consuming a WCF-Webservice. In my case it turned
out to be a configuration error on the server side. Maybe something is configured differently
on the one server where this happens to you?
My problem was that the default maximum message size was configured to be too small
on the server and this resulted in the same forced connection closing. There is a default
maximum message size to avoid DOS attacks...
If you are using a WCF client to connect to the service, enable service trace logging in your client application with the following config:
<system.diagnostics>
<trace autoflush="true" />
<sources>
<source name="System.ServiceModel"
switchValue="Error"
propagateActivity="true">
<listeners>
<add name="sdt"
type="System.Diagnostics.XmlWriterTraceListener"
initializeData= "ErrorTrace.svclog"
/>
</listeners>
</source>
</sources>
</system.diagnostics>
Download the windows sdk and you have a nice trace viewer for these log files. It helps you get to the bottom of errors in WCF communication.
Using cross platform communication sometimes it happens (once happened to my code) that the exception thrown is not the real description of what is happening inside.
One cause of this exception is that your response time is a little lesser than time required by the webservice method to complete. So try to increase the timeout in your app.config.
If it doesn't work there could be two possible problems in your case.
If SSL is used then there is problem with SSL certificate validity.
There are some invalid characters used in XML for example your platform doesn't support Unicode characters and there is some un-supported character used in XML.
But I hope just increasing the timeout will fix this.
I did get similar error and cause was exception in XML serialization. Mostly if xmlserializer tries to read some property and that get method raises an exception due to some database connection already closed or any resources not available.
Have you tried to log exceptions in error event inside global.asax?
Sometimes if global.asax does not raise error event, then only way to log error through response filter. You can add custom response filter in the web.config, in which you will be able to analyze how much XML was correctly serialized and where it might be failing.
http://msdn.microsoft.com/en-us/library/aa479332.aspx
http://www.raboof.com/projects/elmah/
Intermediate "An existing connection was forcibly closed by the remote host" from only one destination sounds like a networking issue to me.
Try getting logs from the server you try to access and from the involved firewalls of both locations.
You may run Fiddler or NetMon / WireShark / Ethereal to diagnose further.
Connection close happen for any circumstance. Make sure the timeout is abundant on the server and the client, make sure there is no recursion in the data you are returning. Circular reference. Serialization is important in this case because the thing is being serialized when returned.
Do a WCF tracer and check the answer there. Any fault in the server will close the connection. If the server requires username, make sure those are correct. Take care of the SSL error. use WCF client to test the service.
This may be a shot in the dark but here is my theory:
The first error is happening on the web service side with a poor exception being thrown, maybe some invalid data is being passing into the service? This could return the error regarding the XML being malformed. I would do several test cases to see what data is being passed into the service and what causes the issue.
The second error I have seen before in a certain circumstance regarding a web service exception being thrown and a try catch wrapped around a using statement for the service. This combination of logic caused an early exit that wasnt cleaned up.
try to check the existing protocols in your last company and compare them with your current company,I mean TCP/Ip,...
Check the app pool recycling configuration in IIS. I have seen this error, for example, when the "Private Memory Limit" is set to a value (say 100mb) and then the w3wp process exceeds this limit which will cause the app pool to be recycled.
This normally isn't a problem since any existing connections are given time to complete and new connections will be processed by the newly spun-up app pool.
If all the connections are not closed within the shutdown time limit though (normally 90 seconds) then they are killed by IIS and the client may raise the "An existing connection was forcibly closed" error.
I am working with a commercial application which is throwing a SocketException with the message,
An existing connection was forcibly closed by the remote host
This happens with a socket connection between client and server. The connection is alive and well, and heaps of data is being transferred, but it then becomes disconnected out of nowhere.
Has anybody seen this before? What could the causes be? I can kind of guess a few causes, but also is there any way to add more into this code to work out what the cause could be?
Any comments / ideas are welcome.
... The latest ...
I have some logging from some .NET tracing,
System.Net.Sockets Verbose: 0 : [8188] Socket#30180123::Send() DateTime=2010-04-07T20:49:48.6317500Z
System.Net.Sockets Error: 0 : [8188] Exception in the Socket#30180123::Send - An existing connection was forcibly closed by the remote host DateTime=2010-04-07T20:49:48.6317500Z
System.Net.Sockets Verbose: 0 : [8188] Exiting Socket#30180123::Send() -> 0#0
Based on other parts of the logging I have seen the fact that it says 0#0 means a packet of 0 bytes length is being sent. But what does that really mean?
One of two possibilities is occurring, and I am not sure which,
The connection is being closed, but data is then being written to the socket, thus creating the exception above. The 0#0 simply means that nothing was sent because the socket was already closed.
The connection is still open, and a packet of zero bytes is being sent (i.e. the code has a bug) and the 0#0 means that a packet of zero bytes is trying to be sent.
What do you reckon? It might be inconclusive I guess, but perhaps someone else has seen this kind of thing?
This generally means that the remote side closed the connection (usually by sending a TCP/IP RST packet). If you're working with a third-party application, the likely causes are:
You are sending malformed data to the application (which could include sending an HTTPS request to an HTTP server)
The network link between the client and server is going down for some reason
You have triggered a bug in the third-party application that caused it to crash
The third-party application has exhausted system resources
It's likely that the first case is what's happening.
You can fire up Wireshark to see exactly what is happening on the wire to narrow down the problem.
Without more specific information, it's unlikely that anyone here can really help you much.
Using TLS 1.2 solved this error.
You can force your application using TLS 1.2 with this (make sure to execute it before calling your service):
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12
Another solution :
Enable strong cryptography in your local machine or server in order to use TLS1.2 because by default it is disabled so only TLS1.0 is used.
To enable strong cryptography , execute these commande in PowerShell with admin privileges :
Set-ItemProperty -Path 'HKLM:\SOFTWARE\Wow6432Node\Microsoft\.NetFramework\v4.0.30319' -Name 'SchUseStrongCrypto' -Value '1' -Type DWord
Set-ItemProperty -Path 'HKLM:\SOFTWARE\Microsoft\.NetFramework\v4.0.30319' -Name 'SchUseStrongCrypto' -Value '1' -Type DWord
You need to reboot your computer for these changes to take effect.
This is not a bug in your code. It is coming from .Net's Socket implementation. If you use the overloaded implementation of EndReceive as below you will not get this exception.
SocketError errorCode;
int nBytesRec = socket.EndReceive(ar, out errorCode);
if (errorCode != SocketError.Success)
{
nBytesRec = 0;
}
Had the same bug. Actually worked in case the traffic was sent using some proxy (fiddler in my case). Updated .NET framework from 4.5.2 to >=4.6 and now everything works fine. The actual request was:
new WebClient().DownloadData("URL");
The exception was:
SocketException: An existing connection was forcibly closed by the
remote host
Simple solution for this common annoying issue:
Just go to your ".context.cs" file (located under ".context.tt" which located under your "*.edmx" file).
Then, add this line to your constructor:
public DBEntities()
: base("name=DBEntities")
{
this.Configuration.ProxyCreationEnabled = false; // ADD THIS LINE!
}
I've got this exception because of circular reference in entity.In entity that look like
public class Catalog
{
public int Id { get; set; }
public int ParentId { get; set; }
public Catalog Parent { get; set; }
public ICollection<Catalog> ChildCatalogs { get; set; }
}
I added [IgnoreDataMemberAttribute] to the Parent property. And that solved the problem.
If Running In A .Net 4.5.2 Service
For me the issue was compounded because the call was running in a .Net 4.5.2 service. I followed #willmaz suggestion but got a new error.
In running the service with logging turned on, I viewed the handshaking with the target site would initiate ok (and send the bearer token) but on the following step to process the Post call, it would seem to drop the auth token and the site would reply with Unauthorized.
Solution
It turned out that the service pool credentials did not have rights to change TLS (?) and when I put in my local admin account into the pool, it all worked.
I had the same issue and managed to resolve it eventually. In my case, the port that the client sends the request to did not have a SSL cert binding to it. So I fixed the issue by binding a SSL cert to the port on the server side. Once that was done, this exception went away.
For anyone getting this exception while reading data from the stream, this may help. I was getting this exception when reading the HttpResponseMessage in a loop like this:
using (var remoteStream = await response.Content.ReadAsStreamAsync())
using (var content = File.Create(DownloadPath))
{
var buffer = new byte[1024];
int read;
while ((read = await remoteStream.ReadAsync(buffer, 0, buffer.Length)) != 0)
{
await content.WriteAsync(buffer, 0, read);
await content.FlushAsync();
}
}
After some time I found out the culprit was the buffer size, which was too small and didn't play well with my weak Azure instance. What helped was to change the code to:
using (Stream remoteStream = await response.Content.ReadAsStreamAsync())
using (FileStream content = File.Create(DownloadPath))
{
await remoteStream.CopyToAsync(content);
}
CopyTo() method has a default buffer size of 81920. The bigger buffer sped up the process and the errors stopped immediately, most likely because the overall download speeds increased. But why would download speed matter in preventing this error?
It is possible that you get disconnected from the server because the download speeds drop below minimum threshold the server is configured to allow. For example, in case the application you are downloading the file from is hosted on IIS, it can be a problem with http.sys configuration:
"Http.sys is the http protocol stack that IIS uses to perform http communication with clients. It has a timer called MinBytesPerSecond that is responsible for killing a connection if its transfer rate drops below some kb/sec threshold. By default, that threshold is set to 240 kb/sec."
The issue is described in this old blogpost from TFS development team and concerns IIS specifically, but may point you in a right direction. It also mentions an old bug related to this http.sys attribute: link
In case you are using Azure app services and increasing the buffer size does not eliminate the problem, try to scale up your machine as well. You will be allocated more resources including connection bandwidth.
I got the same issue while using .NET Framework 4.5. However, when I update the .NET version to 4.7.2 connection issue was resolved. Maybe this is due to SecurityProtocol support issue.
For me, it was because the app server I was trying to send email from was not added to our company's SMTP server's allowed list.
I just had to put in SMTP access request for that app server.
This is how it was added by the infrastructure team (I don't know how to do these steps myself but this is what they said they did):
1. Log into active L.B.
2. Select: Local Traffic > iRules > Data Group List
3. Select the appropriate Data Group
4. Enter the app server's IP address
5. Select: Add
6. Select: Update
7. Sync config changes
Yet another possibility for this error to occur is if you tried to connect to a third-party server with invalid credentials too many times and a system like Fail2ban is blocking your IP address.
I was trying to connect to the MQTT broker using the GO client,
broker address was given as address + port, or tcp://address:port
Example: ❌
mqtt://test.mosquitto.org
which indicates that you wish to establish an unencrypted connection.
To request MQTT over TLS use one of ssl, tls, mqtts, mqtt+ssl or tcps.
Example: ✅
mqtts://test.mosquitto.org
In my case, enable the IIS server & then restart and check again.
We are using a SpringBoot service. Our restTemplate code looks like below:
#Bean
public RestTemplate restTemplate(final RestTemplateBuilder builder) {
return builder.requestFactory(() -> {
final ConnectionPool okHttpConnectionPool =
new ConnectionPool(50, 30, TimeUnit.SECONDS);
final OkHttpClient okHttpClient =
new OkHttpClient.Builder().connectionPool(okHttpConnectionPool)
// .connectTimeout(30, TimeUnit.SECONDS)
.retryOnConnectionFailure(false).build();
return new OkHttp3ClientHttpRequestFactory(okHttpClient);
}).build();
}
All our call were failing after the ReadTimeout set for the restTemplate. We increased the time, and our issue was resolved.
This error occurred in my application with the CIP-protocol whenever I didn't Send or received data in less than 10s.
This was caused by the use of the forward open method. You can avoid this by working with an other method, or to install an update rate of less the 10s that maintain your forward-open-connection.
My WCF server needs to go up and down on a regular basis, the client sometimes uses the server, but if it is down the client just ignore it.
So each time I need to use the server services I check the connection state and if it's not open I open it.
The problem is that if I attempt to open while the server is down there is a delay which hits performance.
My question is, is there a way to do some kind of myClient.CanOpen()? so I'd know if there is any point to open the connection to the server.
There is an implementation of WS-Discovery that would allow you to listen for up/down announcements for your service. This is also a very convenient form of service address resolution because it utilizes UDP multicast messages to find the service, rather than configuring one set address on the client.
WS-Discovery for WCF
There's also an implementation done by a Microsoft employee:
WS-Discovery Sample Implementation
.NET 4.0 will include this natively. You can read about .NET 4.0's implementation on Jesus Rodriguez's blog. It has a great chart that details the ad-hoc communication that goes on in WS-Disco Using WS-Discovery in WCF 4.0
Another thing you might consider, especially if your messages are largely one-way, is a protocol that works natively disconnected, like MSMQ. I don't know what your design for your application looks like, but MSMQ would allow a client to send a message regardless of the state of the service and the service will get it when it comes back up. This way your client doesn't have to block quite so much trying to get confirmation that a service is up before communicating... it'll just fire and forget.
Hope this helps.
If you are doing a synchronous call expecting a server timeout in an application with a user interface, you should be doing it in another thread. I doubt that the performance hit is due to exception overhead.
Is your performance penalty in CPU load, gui availability or wall clock time?
You could investigate to see if you can create a custom binding on TCP, but with faster timeout.
I assume you know that "IsOneWay=true" is faster than request->response in your case because you wouldn't be expecting a response anyway, but then you are not getting confirmation or return values.
You could also implement a two-way communication that is not request->response.
If you were in a local network it might be possible to broadcast a signal to say that a new server is up. The client would need to listen for the broadcast signal and respond accordingly.
Here's what I'm using and it works like a charm. And btw, the ServiceController class lives in namespace 'System.ServiceProcess'.
try
{
ServiceController sc = new ServiceController("Service Name", "Computer's IP Address");
Console.WriteLine("The service status is currently set to {0}",
sc.Status.ToString());
if ((sc.Status.Equals(ServiceControllerStatus.Stopped)) ||
(sc.Status.Equals(ServiceControllerStatus.StopPending)))
{
Console.WriteLine("Service is Stopped, Ending the application...");
Console.Read();
EndApplication();
}
else
{
Console.WriteLine("Service is Started...");
}
}
catch (Exception)
{
Console.WriteLine("Error Occurred trying to access the Server service...");
Console.Read();
EndApplication();
}
I don't think it's possible doing a server side call to your Client to inform him that you the service has been started ... Best method i can see is having a client method figuring out where or not the service is open and in good condition. Unless I am missing some functionality of WCF ...
There is a good blogpost WCF: Availability of the WCF services if you are interested in a read.
Every now and then in a high volume .NET application, you might see this exception when you try to execute a query:
System.Data.SqlClient.SqlException: A transport-level error has
occurred when sending the request to the server.
According to my research, this is something that "just happens" and not much can be done to prevent it. It does not happen as a result of a bad query, and generally cannot be duplicated. It just crops up maybe once every few days in a busy OLTP system when the TCP connection to the database goes bad for some reason.
I am forced to detect this error by parsing the exception message, and then retrying the entire operation from scratch, to include using a new connection. None of that is pretty.
Anybody have any alternate solutions?
I posted an answer on another question on another topic that might have some use here. That answer involved SMB connections, not SQL. However it was identical in that it involved a low-level transport error.
What we found was that in a heavy load situation, it was fairly easy for the remote server to time out connections at the TCP layer simply because the server was busy. Part of the reason was the defaults for how many times TCP will retransmit data on Windows weren't appropriate for our situation.
Take a look at the registry settings for tuning TCP/IP on Windows. In particular you want to look at TcpMaxDataRetransmissions and maybe TcpMaxConnectRetransmissions. These default to 5 and 2 respectively, try upping them a little bit on the client system and duplicate the load situation.
Don't go crazy! TCP doubles the timeout with each successive retransmission, so the timeout behavior for bad connections can go exponential on you if you increase these too much. As I recall upping TcpMaxDataRetransmissions to 6 or 7 solved our problem in the vast majority of cases.
This blog post by Michael Aspengren explains the error message "A transport-level error has occurred when sending the request to the server."
To answer your original question:
A more elegant way to detect this particular error, without parsing the error message, is to inspect the Number property of the SqlException.
(This actually returns the error number from the first SqlError in the Errors collection, but in your case the transport error should be the only one in the collection.)
I had the same problem albeit it was with service requests to a SQL DB.
This is what I had in my service error log:
System.Data.SqlClient.SqlException: A transport-level error has occurred when sending the request to the server. (provider: TCP Provider, error: 0 - An existing connection was forcibly closed by the remote host.)
I have a C# test suite that tests a service. The service and DB were both on external servers so I thought that might be the issue. So I deployed the service and DB locally to no avail. The issue continued. The test suite isn't even a hard pressing performance test at all, so I had no idea what was happening. The same test was failing each time, but when I disabled that test, another one would fail continuously.
I tried other methods suggested on the Internet that didn't work either:
Increase the registry values of TcpMaxDataRetransmissions and TcpMaxConnectRetransmissions.
Disable the "Shared Memory" option within SQL Server Configuration Manager under "Client Protocols" and sort TCP/IP to 1st in the list.
This might occur when you are testing scalability with a large number of client connection attempts. To resolve this issue, use the regedit.exe utility to add a new DWORD value named SynAttackProtect to the registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\ with value data of 00000000.
My last resort was to use the old age saying "Try and try again". So I have nested try-catch statements to ensure that if the TCP/IP connection is lost in the lower communications protocol that it does't just give up there but tries again. This is now working for me, however it's not a very elegant solution.
use Enterprise Services with transactional components
I have seen this happen in my own environment a number of times. The client application in this case is installed on many machines. Some of those machines happen to be laptops people were leaving the application open disconnecting it and then plugging it back in and attempting to use it. This will then cause the error you have mentioned.
My first point would be to look at the network and ensure that servers aren't on DHCP and renewing IP Addresses causing this error. If that isn't the case then you have to start trawlling through your event logs looking for other network related.
Unfortunately it is as stated above a network error. The main thing you can do is just monitor the connections using a tool like netmon and work back from there.
Good Luck.
You should also check hardware connectivity to the database.
Perhaps this thread will be helpful:
http://channel9.msdn.com/forums/TechOff/234271-Conenction-forcibly-closed-SQL-2005/
I'm using reliability layer around my DB commands (abstracted away in the repository interfaece). Basically that's just code that intercepts any expected exception (DbException and also InvalidOperationException, that happens to get thrown on connectivity issues), logs it, captures statistics and retries everything again.
With that reliability layer present, the service has been able to survive stress-testing gracefully (constant dead-locks, network failures etc). Production is far less hostile than that.
PS: There is more on that here (along with a simple way to define reliability with the interception DSL)
I had the same problem. I asked my network geek friends, and all said what people have replied here: Its the connection between the computer and the database server. In my case it was my Internet Service Provider, or there router that was the problem. After a Router update, the problem went away. But do you have any other drop-outs of internet connection from you're computer or server? I had...
I experienced the transport error this morning in SSMS while connected to SQL 2008 R2 Express.
I was trying to import a CSV with \r\n. I coded my row terminator for 0x0d0x0a. When I changed it to 0x0a, the error stopped. I can change it back and forth and watch it happen/not happen.
BULK INSERT #t1 FROM 'C:\123\Import123.csv' WITH
( FIRSTROW = 1, FIELDTERMINATOR = ',', ROWTERMINATOR = '0x0d0x0a' )
I suspect I am not writing my row terminator correctly because SQL parses one character at a time right while I'm trying to pass two characters.
Anyhow, this error is 4 years old now, but it may provide a bit of information for the next user.
I just wanted to post a fix here that worked for our company on new software we've installed. We were getting the following error since day 1 on the client log file: Server was unable to process request. ---> A transport-level error has occurred when receiving results from the server. (provider: TCP Provider, error: 0 - The semaphore timeout period has expired.) ---> The semaphore timeout period has expired.
What completely fixed the problem was to set up a link aggregate (LAG) on our switch. Our Dell FX1 server has redundant fiber lines coming out of the back of it. We did not realize that the switch they're plugged into needed to have a LAG configured on those two ports. See details here: https://docs.meraki.com/display/MS/Switch+Ports#SwitchPorts-LinkAggregation