I have Odoo 12 set up on a server and our MailInABox server separate.

I have installed Postfix on the odoo server and relay is working correctly going through the MIAB server.

In odoo, I have it set for TLS and port 587 which is what MIAB defaults to. But when I test the connection I get the following error:

Connection Test Failed! Here is what we got instead:
535
5.7.8 Error: authentication failed: UGFzc3dvcmQ6 

I have ensured that the catchall and bounce aliases are in the system parameters.

Any help would be greatly appreciated.

thanks,

Dave