Common error messages and actions for external SMTP server

Use this reference to troubleshoot errors when configuring an external SMTP server.

The following table lists the common error messages and recommended actions for configuring external SMTP server.

Error Message	Recommended Action
Unknown SMTP host	Check that the SMTP Server Name is correct.
Could not connect to SMTP host	Check that the SMTP Port is correct. If the port is correct, the SMTP server might be experiencing a temporary issue. Wait a few minutes and try again.
Connect timed out
Authentication failed: Bad username / password	Check whether your username and password are correct.
Authentication failed	Check whether your username and password, or OAuth 2.0 provider configuration are correct.
Authentication required	Check if you have configured the Authentication field.
Read timed out	Check that you have entered the correct values for the following fields: SMTP SocketFactory Port SMTP SocketFactory Class SMTP SocketFactory Fallback
Could not convert socket to TLS