I am using .net version 3.5 for sending mails though my web application
I get the following error:
The SMTP server requires a secure connection or the client was not authenticated.
The server response was: 5.7.1 Client was not authenticated
What could be causing this?
Source from here http://www.systemnetmail.com/faq/4.2.aspx
//create the mail message
MailMessage mail = new MailMessage();
//set the addresses
mail.From = new MailAddress("me#mycompany.com");
mail.To.Add("you#yourcompany.com");
//set the content
mail.Subject = "This is an email";
mail.Body = "this is the body content of the email.";
//send the message
SmtpClient smtp = new SmtpClient("127.0.0.1");
//to authenticate we set the username and password properites on the SmtpClient
smtp.Credentials = new NetworkCredential("username", "secret");
smtp.Send(mail);
EDIT: This error means what it's written: smtp server needs authentication information (username and password). So, you need set SmtpClient.Credentials.
Try:
smtpclient.EnableSsl = true;
The SMTP server requires a secure
connection or the client was not
authenticated. The server response
was: 5.7.1 Client was not
authenticated
so you need to authenticate by adding credentials
smtpClient.Credentials = new NetworkCredential("username", "password");
Related
Error: The SMTP server requires a secure connecton or the client was not authenticated. The server
response was: 5.7.0 Authentication Required. Learn more at.
private void SendMail(string email, string firstname)
{
MailAddress from = new MailAddress($"{email}", $"{firstname}");
MailAddress to = new MailAddress($"{email}");
MailMessage m = new MailMessage(from, to);
m.Subject = "TEST";
m.Body = "<h2>TEST</h2>";
m.IsBodyHtml = true;
SmtpClient smtp = new SmtpClient("smtp.gmail.com", 587);
smtp.Credentials = new NetworkCredential("jewralyapp#mail.ru", "password");
smtp.EnableSsl = true;
smtp.Send(m);
}
I want to send a letter to the mail, but the error that I indicated above comes out, here is the code, can you tell me what is wrong?
I see that your email is #mail.ru and the server is gmail, is that correct? I think you need to use your gmail account.
You also need enable weaker credentials on your gmail account. Forgot what they actually call it but it's on gmail security setting.
I had also faced the same problem.
Your SmtpClient is gmail, but you are using "jewralyapp#mail.ru"!!!
Make sure to set "Less secure app access" to ON in your Gmail security setting.
In my case, the problem was solved.
This is how I am sending email:
MailMessage m = new MailMessage();
m.From = new MailAddress("support#big-apps.org", "Big Apps.");
m.To.Add(new MailAddress("faizan003#gmail.com"));
m.Subject = "Test Subject";
m.Body = String.Format("This is Test email");
SmtpClient smtp = new SmtpClient();
smtp.Host = "smtp.gmail.com";
smtp.Port = 465;
smtp.EnableSsl = true;
smtp.Credentials = new System.Net.NetworkCredential()
{
UserName = "support#big-apps.org",
Password = "mypassword"
};
smtp.EnableSsl = true;
smtp.Send(m);
Is there any setting that I need to enable in G Suite Admin?
I need to send email from support#big-apps.org
The port 465 is the issue. The SmtpClient EnableSsl option is actually using TLS. Gmail's TLS port is 587.
From Microsoft's Documentation:
https://learn.microsoft.com/en-us/dotnet/api/system.net.mail.smtpclient.enablessl?view=netframework-4.8
The SmtpClient class only supports the SMTP Service Extension for Secure SMTP over Transport Layer Security as defined in RFC 3207. In this mode, the SMTP session begins on an unencrypted channel, then a STARTTLS command is issued by the client to the server to switch to secure communication using SSL. See RFC 3207 published by the Internet Engineering Task Force (IETF) for more information.
An alternate connection method is where an SSL session is established up front before any protocol commands are sent. This connection method is sometimes called SMTP/SSL, SMTP over SSL, or SMTPS and by default uses port 465. This alternate connection method using SSL is not currently supported.
So far this is what i've tried, I want to send an email to our school email account with format of jcvborlagdan#mymail.mapua.edu.ph or something like jcborlagdan#mapua.edu.ph. I'm sure that this is an outlook account so I took the smtp settings for outlook, but when I do this I keep on encountering the following error:
Failure sending mail.
What am I doing wrong here? I already search for the error but all of the answers are showing same syntax with mine except for the smtp settings. So there must be something wrong with my smtp settings for outlook.
SmtpClient smtpClient = new SmtpClient("smtp-mail.outlook.com", 25); //587
smtpClient.Credentials = new System.Net.NetworkCredential("mymail#mapua.edu.ph", "myPassword");
smtpClient.UseDefaultCredentials = true;
smtpClient.DeliveryMethod = SmtpDeliveryMethod.Network;
smtpClient.EnableSsl = true;
MailMessage mail = new MailMessage();
mail.From = new MailAddress("mymail#mapua.edu.ph", "CTMIS-no-reply");
mail.To.Add(new MailAddress("carlo.borlagdan#the-v.net"));
mail.CC.Add(new MailAddress("jcborlagdan#ymail.com"));
smtpClient.Send(mail);
Some small changes were required to get your code working.
UseDefaultCredentials need to be set to False since you want to use custom credentials
UseDefaultCredentials need to be set to False before setting the credentials.
SSL port is 587 for Outlook.
Thats all.
Here is the code fixed.
SmtpClient smtpClient = new SmtpClient("smtp-mail.outlook.com", 587); //587
smtpClient.UseDefaultCredentials = false;
smtpClient.Credentials = new System.Net.NetworkCredential("mymail#mapua.edu.ph", "myPassword");
smtpClient.DeliveryMethod = SmtpDeliveryMethod.Network;
smtpClient.EnableSsl = true;
MailMessage mail = new MailMessage();
mail.From = new MailAddress("mymail#mapua.edu.ph", "CTMIS-no-reply");
mail.To.Add(new MailAddress("carlo.borlagdan#the-v.net"));
mail.CC.Add(new MailAddress("jcborlagdan#ymail.com"));
smtpClient.Send(mail);
Concerning UseDefaultCredentials
From MSDN:
Some SMTP servers require that the client be authenticated before the server sends e-mail on its behalf. Set this property to true when this SmtpClient object should, if requested by the server, authenticate using the default credentials of the currently logged on user.
--
Since you don't want to authenticate using your Windows credentials, the
property is set to False. As for the fact you need to put it before, I have no official source but it simply does not work if you set your credentials before setting that property to false.
I have a web with contact form - I want feedback being sent to my gmail account. For this I created another, dummy gmail account for sending these messages. Code looks like this
MailMessage msg = new MailMessage();
msg.To.Add("to_mail#gmail.com");
msg.From = new MailAddress("from_mail#gmail.com");
msg.Subject = "Feedback";
msg.Body = txtName.Text + " " + txtEmail.Text + " " + txtMessage.Text;
msg.IsBodyHtml = true;
SmtpClient client = new SmtpClient();
client.Host = "smtp.gmail.com";
client.Port = 587;
client.UseDefaultCredentials = false;
client.Credentials = new System.Net.NetworkCredential("from_mail#gmail.com", "password");
client.DeliveryMethod = SmtpDeliveryMethod.Network;
client.EnableSsl = true;
client.Send(msg);
This code works fine when I run it from localhost from my VS project, but once I compile it and upload to the web, its stops working with this error.
System.Net.Mail.SmtpException: The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required.
Does anyone have an idea what caused it and how to fix it? I already enabled access for less secure applications in my gmail account. Tried also 465 port, but that doesnt work either.
Thank a lot, Jozef
Finally found an answer. Had to click this link with my "From" Gmail account logged in.
https://accounts.google.com/b/0/DisplayUnlockCaptcha
Possible Reason:
In gmail, If the current login region and the previous login region is
different, then gmail ask us some security questions before login. So
better try to login once via browser in the system which you are using
that C# app.
I am currently using Google Apps to send SMTP e-mails. If my project deploys some of the information that i am going to be sending will be confidential and i would like to make sure the transmission is secure. Can anyone please let me know what i need to do to ensure that i send a safe e-mail using smtp through the google apps smtp server? smtp.google.com.
Any help greatly appreciated.
From what I have been told i need to force Https and have a SSL cert in order to do this. I don't know if this is true?
You Can Use 'smtp.EnableSsl = true' For Enable SSL for security.
MailMessage mail = new MailMessage();
mail.To.Add("" + to + "");
mail.From = new MailAddress("" + from + "");
mail.Subject = "Email using Gmail";
string Body = "Hi, this mail is to test sending mail" +
"";
mail.Body = Body;
mail.IsBodyHtml = true;
Attachment at = new Attachment(Server.MapPath("~/ExcelFile/TestCSV.csv"));
mail.Attachments.Add(at);
mail.Priority = MailPriority.High;
SmtpClient smtp = new SmtpClient();
smtp.Host = "smtp.gmail.com"; //Or Your SMTP Server Address
smtp.Credentials = new System.Net.NetworkCredential(""+ username +"", ""+ password +"");
smtp.EnableSsl = true;
smtp.Port = 587;
smtp.Send(mail);
To enforce Network Security you have to use SSL. to enforce security of the data going from your webserver to mail server you need to send your mail over SSL. and to secure the HTTP request that triggers the mail action you need to enforce SSL over HTTP.
But the question is Security in what context ? If you need network security to ensure a 3rd party cannot eavesdrop or manipulate then SSL is your way to go.