> made a prediction with high confidence

Do you somehow track the amount of false positives these predictions generate? How do you tune the prediction to not generate too many false positives?

> but in real life, you absolutely need to be proactive

Why is Microsoft the only provider who needs to do such proactive blocking? Why don't you need to do that for email addresses associated with Office 365?

> I think you should give me even more detailed feedback since there’s not much I can do except give a vague high level explanation unless you help me by being specific.

My story is very much the same as for everybody else having the same trouble, including the person whose blog post sparked this discussion: A root server for personal use located in the data center of a mid-sized hoster, running a mail server as part of its duties. In my case the whole mail setup runs on IP-addresses separate from everything else. Mail volume to Microsoft would probably be on average 1-2 emails per month. No issues whatsoever getting emails delivered to other mail providers, only to Microsoft. This whole setup is in place since several years.