Phabricator sends emails with header e.g.,
But when one replies to it, one gets an error email:
Error Processing Mail (Empty Mail) Your email to Phabricator was not processed, because an error occurred while trying to handle it: Phabricator can not process this mail because no application knows how to handle it. Check that the address you sent it to is correct. (No concrete, enabled subclass of PhabricatorMailReceiver can accept this mail.)
Therefore in the initial mail it should say "Don't Reply to this mail." and
remove the Reply-to:, if not planning to process the mail.