Thanks for the info. I’ll have another go with a spare domain to see if I can get it to working across the board.

Did you ever manage to get off hotmail/outlook spam filters? I ran my own server for years and had no issues with gmail, but was never able to reliably send to hotmail. That was the nail in the coffin in the end as so many businesses I communicate with were on outlook and my mail would always goto spam causing endless issues.

How does a current day BBS work? Landline phone connections are a thing of the past here.