I tried to sign up for this forum which needs me to click a link in an confirmation email sent to me.
However, that mail never reached me.
As I run my own mailserver the postfix logs told me why:
Jun 4 14:03:10 mail postfix/smtpd: warning: hostname mx-out-01a.sjc3.discourse.org does not resolve to address 184.108.40.206: Temporary failure in name resolution
Jun 4 14:03:10 mail postfix/smtpd: connect from unknown[220.127.116.11]
Jun 4 14:03:11 mail postfix/smtpd: NOQUEUE: reject: RCPT from unknown[18.104.22.168]: 450 4.7.25 Client host rejected: cannot find your hostname, [22.214.171.124]; from=<cosmos1+verp-585d7[censoredforprivacy]@discoursemail.com> email@example.com proto=ESMTP helo=<mx-out-01a.sjc3.discourse.cloud>
My mailserver is configured to
The only chance to receive that confirmation mail was to temporarely deactivate the option(s) above.
As every good mailserver should have those options turned on I suggest changing something on the sender side. Maybe a lot of people can not sign up here because of that.