Relay stopped working

I had been using mailinabox as our email server for the last year, at some point a program we use to send emails on a separate server stopped sending.

I get the following error:

Nov 27 20:08:23 localhost postfix/smtp[4390]: 8FA76615E0:,[X.X.X.X]:587, delay=6.6, delays=0/0.02/6.6/0, dsn=4.7.8, status=deferred (SASL authentication failed; server[X.X.X.X] said: 535 5.7.8 Error: authentication failed: )

I’ve tried reinstalling and setting it up again but keep getting the same error over and over. Sending mail the traditional way works fine.

The issue is not MiaB …

The “program we use to send emails on a separate server” is not correctly authenticating. You need to check the settings within THAT program to insure that it is presenting the correct credentials to the SMTP server within MiaB.