The SMTP server does not support authentication.

[Richard Pieneman]

I'm using 3CX Professional V15.5 for a few months on a Microsoft Windows Server 2012 R2 machine.

In the beginning I setup a Office365 mail account to send emails, that works without any troubles.
From one to another day it stopped working (no Windows update or 3CX update/change was made).
I could not make it work again, so I tried to fall back to the 3CX SMTP server, but this gives the same error: "The SMTP server does not support authentication." even as Outlook.com and Gmail (also tried as Custom SMTP server).

After all my tests I restarted the 3CX services (and sometimes a reboot of the machine)

The message in the 3CXSystemService.log:

2018/08/16 09:27:16.888|3696|0018|Excpt|System.NotSupportedException: The SMTP server does not support authentication.
   at MailKit.Net.Smtp.SmtpClient.<AuthenticateAsync>d__64.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at MailKit.Net.Smtp.SmtpClient.Authenticate(Encoding encoding, ICredentials credentials, CancellationToken cancellationToken)
   at MailKit.MailService.Authenticate(String userName, String password, CancellationToken cancellationToken)
   at TcxMail.MailTemplateSender.Send(XDocument template, Func`2 getParameter, String mailTo, IEnumerable`1 attachments, Func`2 needEncode)
   at _3cxSystemService.ExtSheduller.WelcomeEmailSender.SendWelcome(Extension ext)
   at _3cxSystemService.ExtSheduller.WelcomeEmailSender.SendingProc()

I'm out of solutions, does anyone has any ideas?

 

[Dominik Oelmaier]

Hello Richard,

Please note that 2 step authentication process does not work with 3CX.

If you use Google as your mail server and you also have 2 step verification setup on your Google account you need to generate an app specific password.
Sign into Google
Google Apps - My Account - Sign In and Security - Password and Sign In Method - App Passwords.
Generate a password and enter it on the 3CX mail server settings.

best regards,

Dominik Oelmaier

 

[Richard Pieneman]

Hello Richard,

Please note that 2 step authentication process does not work with 3CX.

If you use Google as your mail server and you also have 2 step verification setup on your Google account you need to generate an app specific password.
Sign into Google
Google Apps - My Account - Sign In and Security - Password and Sign In Method - App Passwords.
Generate a password and enter it on the 3CX mail server settings.

best regards,

Dominik Oelmaier

Hi Dominik,

Thanks for you're reply!
Actually, the problem exist with all Mail Servers

While testing Gmail I didn't use 2 step verification, so that's not the problem.

Best regards,

Richard

 

[Dominik Oelmaier]

Okay, sorry that is the main problem with the 3cx SMTP Server.

I will search for a Answer to solve your problem. After that i reply immediatly to you!


best regards,

Dominik Oelmaier

 

[YiannisH_3CX]

Hello @Richard Pieneman

Please set the SMTP server of the PBX to 3CX SMTP. Click OK to apply the change and then press the test button.
Send us a screenshot of the error you get under the email settings.

 

[Richard Pieneman]

Hello @Richard Pieneman

Please set the SMTP server of the PBX to 3CX SMTP. Click OK to apply the change and then press the test button.
Send us a screenshot of the error you get under the email settings.

Hi Yiannis,

See here, I also restarted the server after change to "3CX SMTP server"

 

[YiannisH_3CX]

Did your public IP change recently? Does your FQDN resolve to the correct IP address? Are you using a static or Dynamic IP?
Also do you have a failover server?

 

[Richard Pieneman]

Did your public IP change recently? Does your FQDN resolve to the correct IP address? Are you using a static or Dynamic IP?
Also do you have a failover server?

No nothing has changed.

FQDN reach the right IP, IP is static and I do not have a failover server.

It seems that mail left the building (I see SMTP traffic trough my firewall), but it wont reach the receiver and give the authentication message in 3CX.

 

[YiannisH_3CX]

Please make sure that there are no Windows updates pending and try again after installing them .If the issue still persists i would recommend creating a ticket with our support department so they can take a look at the issue.