I have MIAB all setup and working for most situations. However, I have a few endpoints that cannot send email out using MIAB.
I tried to use Outlook and added the account credentials and everything works as expected. However, when I try to send email via, for example, my pfSense firewall I get an error:
In the new version, authentication on port 25 is now disabled. (This is in the changelog. It’s one of the few functionality changes in this release.) If you’re connecting on port 25, that’s probably the problem — you have to connect on port 587 using STARTTLS. If that’s not the problem, let us know!