Can't configure local mail relay without authentication

Bug
#1

Please describe what you are doing to trigger the bug: Trying to configure local mail relay w/o authentication using :192.168.15.2:25" and the host. Receive error.

Please describe what you expect to happen (but doesn’t): Mail relay configured successfully

Please describe what actually happens (the wrong behaviour): Failed to send the email: x509: cannot validate certificate for 192.168.15.2 because it doesn’t contain any IP SANs

#2

It looks like your mail relay is accepting TLS connections without a proper certificate. I think the relay should be configured to disable TLS.

#3

Perhaps, but since I’m telling you to use port 25, why is it even looking/checking? That’s not a TLS port. I have no issue at all with other services going through this mail relay.