On Mon, Nov 22, 2021, Aaron Poffenberger wrote: > <user>@*sbcglobal.net*: 550 5.7.1 Connections not accepted from > servers without a valid sender domain.alph758 Fix reverse DNS for 198.51.100.1
Do you have the real DSN? Does it say during which stage this error happened? Or does your server log show it? > I know this is related to Message-ID because if I go into muttrc(5) > and put `set hostname="example.com"` and send again to > u...@sbcglobal.net, the message goes through without issue. That changes more than the Id, so it doesn't implement the test I suggested. Do you happen to have an sbcglobal.net or att.net address which could be used for real testing with some tool which allows to observe the SMTP dialogue?
