Mailspring not setting up account with Modoboa - using fake email address scares Postfix!

Mailspring has been working really well the last few days I’ve had it. I’ve run into a problem though with setting up some email accounts. It’s using a mail server called Modoboa, mostly Postfix, Dovecot and the like. However, while IMAP passes the check when pressing “connect account” Postfix is not so kind. It says SMTP connection error at the top, and the logs read:

Dec 25 16:58:21 mo postfix/submission/smtpd[2444]: NOQUEUE: reject: RCPT from 451 4.3.5 Recipient address rejected: Server configuration problem; proto=ESMTP helo=<Mac-mini.local>

I’m not sure if the problem is with Mailspring using as a test or if there is some other config problem with the server. Anyhow, I’ve never seen an error like that before.



EDIT: I just tried adding the account to another MUA and got the same invalid error … so never mind it is a server config problem.