Hongwei Li wrote:
Recently, users say that they cannot use Outlook to send emails out if they set SSL connection with port 587 for outgoing server and 993 for incoming server.
Port 587 isn't an "SSL" port. It's the MSA port, and probably supports TLS. If Outlook is configured to do SSL rather than TLS, it's not going to work.
Port 465 is the SMTP "SSL" port.
