I'm attempting to set up an auto-responder address on a domain. The purpose is just to test the email round-tripping.
The email account email@example.com has been created and a rule created for this mailbox that replies with a template to any emails received.
When I send an email to the echo@ account from another mailbox on the domain, it works fine.
When I send an email to the echo@ account from another mailbox on an external domain, it does not work.
I have the rule respond & then move the email to a folder. So I can see that the emails from the external domain ARE being received by the echo@ mailbox.
I've tested just sending a new email to an external domain account and that does not work either. The recipient never gets the email, and the echo@ account never gets any error message or failed delivery notification. Other users on the domain CAN send outbound to external domain accounts. Just not echo@