How did you know to contact Microsoft to have them whitelist your IP? Was that from a DMARC report? This is the sort of thing that puts me off self-hosting ema

How did you know to contact Microsoft to have them whitelist your IP? Was that from a DMARC report? This is the sort of thing that puts me off self-hosting email, as much as I'd like to do it -- it seems like a huge amount of effort, tracking down who I need to shout at this week to have them whitelist my IP address.