I am trying to send out an email from my windows form application. I have seen a lot of similar posts, but none seem to work. But when I change my settings in gmail to allow less secure apps, the code works. But I don't want to make my account vulnerable for this application. Here's the code and error I get if I don't allow less secure apps.
MailMessage mail = new MailMessage("abc#gmail.com", "xyz#gmail.com", "Test Automation", "Did you receive this?");
SmtpClient client = new SmtpClient("smtp.gmail.com");
client.Port = 587;
client.Credentials = new NetworkCredential("abc#gmail.com", "password");
client.EnableSsl = true;
client.Send(mail);
MessageBox.Show("Mail Sent", "success");
An unhandled exception of type 'System.Net.Mail.SmtpException'
occurred in System.dll
Additional information: The SMTP server requires a secure connection
or the client was not authenticated. The server response was: 5.5.1
Authentication Required.
Please help!
P.S. : I created an outlook account using my gmail and when i put in the oulook server and credentials, the code works. So is it the issue with new gmail security changes? Other similar questions have their problem solved, but I keep having the same errors after trying pretty much every solution.
If you don't have 2 factor
Enable "Less Secure Apps"
https://www.google.com/settings/security/lesssecureapps
If you have 2 factor authentication
You can make an "App Password". Go to the ling below and add a custom app (just write any name you want, name not important just used for your own "bookkeeping") then use that password as the password.
client.Credentials = new NetworkCredential("From#gmail.com", "Generated Password");
https://security.google.com/settings/u/1/security/apppasswords
NOTE:
If you get "The setting you are looking for is not available for your account" then use "less secure app"
Related
I need to use a company shared account (email address is removed for privacy) to send notifications, but fails all the time. I tried all possible codes with no luck.
So, I had a little suspicious about the account. Then I used my office 365 work account, and it is working as expected. But I still need to use the shared account.
The error information is as follows:
Message = "The SMTP server requires a secure connection or the client
was not authenticated. The server response was: 5.7.57 SMTP; Client
was not authenticated to send anonymous mail during MAIL FROM
[D*******8.na***11.prod.outlook.com]"
var message = new MailMessage("from", "to", "MySubject", "MyBody");
SmtpClient client = new SmtpClient("outlook.office365.com");
client.EnableSsl = true;
client.Port = 587;
client.DeliveryMethod = SmtpDeliveryMethod.Network;
client.UseDefaultCredentials = false;
client.Credentials = new NetworkCredential("username", "password");
client.Send(message);
If your account has multi-factor authentication enabled you'll need to use an "app password" for your Office 365 account instead of a regular one that you use to log on.
See https://learn.microsoft.com/en-us/azure/active-directory/user-help/multi-factor-authentication-end-user-app-passwords for how to set one up.
This question already has answers here:
mail sending with network credential as true in windows form not working
(2 answers)
Closed 7 years ago.
I'm working in windows application and C#, I am using following code to send email. The Code not works correctly in my system:
MailMessage mailmsg = new MailMessage();
SmtpClient smtpclient = new SmtpClient();
mailmsg.To.Add(txtTo.Text);
mailmsg.CC.Add(txtCC.Text);
mailmsg.Subject = txtSubj.Text;
mailmsg.From = new MailAddress("buvana#gmail.com");
mailmsg.Body = txtbody.Text;
smtpclient.Port = 587;
smtpclient.Host = "smtp.gmail.com";
smtpclient.EnableSsl = true;
smtpclient.UseDefaultCredentials = false;
smtpclient.Credentials = new NetworkCredential("buvana#gmail.com", "*********");
smtpclient.Send(mailmsg);
How to solve this problem.
Received this error:
SMTP server requires a secure connection or the client was not authenticated
The server response was: 5.5.1 Authentication Required
Your code seems to be fine, useDefaultCredentials is false, port is 587, etc.
I reckon the problem is that you need to configure Gmail to allow Less Secure Applications, following these instructions: https://support.google.com/accounts/answer/6010255?hl=en
Go to the "Less secure apps" section in My Account.
Next to "Access for less secure apps," select Turn on. (Note to Google Apps users: This setting is hidden if your administrator has locked less secure app account access.)
If you are using 2 factor authentication, you'll need to create a new app password for your application and use that to log in.
Our company is switching the SMTP mail server to Office 365. The key issue is the new SMTP server "smtp.office365.com" only supports TLS encryption. Thus I cannot use CredentialCache.DefaultNetworkCredentials to encode my Windows log-in password automatically.
var smtpClient = new SmtpClient("smtp.oldserver.com")
{
Credentials = CredentialCache.DefaultNetworkCredentials
};
const string from = "myemail#xyz.com";
const string recipients = "myemail#xyz.com";
smtpClient.Send(from, recipients, "Test Subject", "Test Body");
Previously this works without any issue. But if I now change the above snippet to:
var smtpClient = new SmtpClient("smtp.office365.com");
smtpClient.EnableSsl = true;
smtpClient.Port = 587;
smtpClient.Credentials = CredentialCache.DefaultNetworkCredentials;
I'm now getting:
Unhandled Exception: System.Net.Mail.SmtpException: The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.7.57 SMTP; Client was not authenticated to send anonymous mail during MAIL FROM
But if I specify my Windows login username and password in the code it works fine:
smtpClient.Credentials = new NetworkCredential("myemail#xyz.com", "mypassword");
So:
Is it possible to encode the password using DefaultNetworkCredentials but make it workable under TLS encryption?
If 1. is not possible, is there a better way to encode my Windows password somewhere else without directly revealing it as plaintext in the code?
The two topics - credentials and encryption - are unrelated. DefaultNetworkCredentials only works when the mail server and your computer belong to the same "network" or to be more accurate, the same or connected Active Directory server. I'm guessing that the old SMTP server was on premise and was part of your office network. The O365 server is in the cloud and doesn't share the AD.
When you provide your credentials explicitly, it works because O365 is able to authenticate you.
There is a possibility to use Azure Active Directory and somehow connect it to your on premise Active Directory. I'm not familiar with the details but I know it can be done. I believe that if you set this up correctly, DefaultNetworkCredentials will start working again.
Details about O365 authentication: https://blogs.office.com/2014/05/13/choosing-a-sign-in-model-for-office-365/
If you need to store the password, you need to store it encrypted. See this answer: Best way to store encryption keys in .NET C#
In my situation I encrypt the section of the web.config that I store these credentials in. I have similarly stored an encrypted version of the credentials in my DB and had a routine to decrypt them in the application.
I'm trying to send email through C#. Although I beleive I've done everything right, it still throws this exception :
"The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required. Learn more at"
At first I thought, it could be a zone/ip/region problem... But when i logged into gmail, there wasn't any warning of that. And to be sure, i've uploaded a file to a website to check from there, still the error was thrown.
Than I've tried changing the port to 465. It didn't work either.
I've first tried with accounts that are managed by a Google Apps account. So I thought it could be it, but it wasn't either...
I'm truly out of ideas right now.
Any of you have an idea ?
Here is the example code :
SmtpClient sm = new SmtpClient("smtp.gmail.com",587);
sm.Credentials = new NetworkCredential("blabla#gmail.com","**");
sm.UseDefaultCredentials = false;
sm.EnableSsl = true;
sm.DeliveryMethod = SmtpDeliveryMethod.Network;
sm.Send("blabla#gmail.com","blabla2#tr3reklam.com","Test","Test");
** Note **
I've checked the account name and password, they both are right.
"Access for less secure apps" must be enabled for the Gmail account used by the NetworkCredential using Google's settings page.
It was caused by 2-Step Verification after all !
It is odd, but without turning on "Allow users to be able to turn on 2-Step verification on" option set to true, I couldn't send any mails.
2-Step verification is still off for the accounts but, probably allowing users to choose for themselves make some security settings in the background.
I couldn't find any documentation about this but I can send now...
Put the code sm.UseDefaultCredentials = false; before sm.Credentials = ...
I have an application that needs to send e-mails. Currently, this is what I am using:
System.Net.Mail.MailMessage MyMailMessage = new System.Net.Mail.MailMessage();
MyMailMessage.From = new System.Net.Mail.MailAddress(fromemail.Text);
MyMailMessage.To.Add(toemail.Text);
MyMailMessage.Subject = subject.Text;
MyMailMessage.Body = body.Text;
System.Net.Mail.SmtpClient SMTPServer = new System.Net.Mail.SmtpClient("smtp.gmail.com");
SMTPServer.Port = 587;
SMTPServer.Credentials = new System.Net.NetworkCredential("email", "password");
SMTPServer.EnableSsl = true;
SMTPServer.Send(MyMailMessage);
Is there a simple way to send an e-mail without having to login to a server? Thank you.
GMail's SMTP server always requires authentication. You may need to setup your own server to send email without authentication.
Configure an SMTP server into your local network (behind a firewall to avoid being a spam source) and use it directly. You can create one in IIS.
There are 2 ways to achieve this:
1) Use your local smtp server (e.g. one with IIS on Win2003/2008 server) and write messages to the local pickup queue). This is possible with minimal changes.
2) You need to resolve the target smtp server. For example when you want to send an email to somebody at msn.com, you'll need to get the MX record for msn.com, e.g. something like mx1.msn.com. You can then directly connect to this SMTP server and send your email to the (local) recipient. Note that there are no built-in ways to resolve the MX-host in .NET (in the sense there are no methods on the Dns class to accomplish this) - you need to do it "manually". Also most SMTP hosts will reject connections from home/residential IP addresses.
You need an SMTP server that does not require authentication, however to stop it being a SPAM server, it needs some other kind of protection like a firewall.