In one case, the content - requested activity alerts from a message board - hasn't changed, and the volume is way *way* under anything suspiciously spambot-y - a hundred emails a week, not per second - but Microsoft have simply refused to accept email to users that have Hotmail / Outlook accounts, despite the only significant change being the IP address it comes from. 

This is even after jumping through all of the hoops in the sometimes very outdated Microsoft 'help' (sic) pages: I strongly suspect that they are blocking the new provider's whole IP address space (or nearly so...) 

Despite having various filters set up to say 'no, it's not spam, how many times do I have to tell you', Gmail still keeps wanting to label fail2ban, logwatch, and other system report emails as spam. 

I look at https://cfenollosa.com/blog/after-self-hosting-my-email-for-twenty-three-years-i-have-thrown-in-the-towel-the-oligopoly-has-won.html and go 'at least it isn't just me' and 'I hope someone takes the oligarchs to someone with teeth', but before I lose all my hair.. 

.. can you still get emails delivered from Bitfolk VPSes to the three reliably to inboxes?

Ian