Outbound email does not work with SMTP host "localhost"
Outbound email functionality works with full SMTP hostname (for example, myserver.mydomain.com); however, it does not work with SMTP host "localhost".
Steps to Reproduce
Send email notification to "localhost". The same configuration works correctly if the full hostname is given.
The root cause of this problem is defect/misconfiguration in the operating environment.
This issue is resolved by making the following change to the operating environment:
Reconfigure MTA to correctly process and filter messages sent in through localhost.