>Can you tell me how you did this? It'll be a bit help! Sorry. It was a few months ago, so I can't remember the intricate details. And my config [as I said pre

>Can you tell me how you did this? It'll be a bit help! Sorry. It was a few months ago, so I can't remember the intricate details. And my config [as I said previously] was slightly out of the norm. But I did use this site which checks the state of your MTA-STS config and gives you a few clues as to what you need to twiddle: https://www.mailhardener.com/tools/mta-sts-validator https://www.mailhardener.com/tools/mta-sts-validator EDIT: have you tried the MIAB forums? They're quite a helpful bunch: https://discourse.mailinabox.email https://discourse.mailinabox.email