Big providers, especially Microsoft, have become extremely heavy handed the last year or so. Now, if a single IP address in a /24 is sending spam, Microsoft wil

Big providers, especially Microsoft, have become extremely heavy handed the last year or so. Now, if a single IP address in a /24 is sending spam, Microsoft will just block the entire /24. And we've had so much difficulty getting Microsoft to walk back that block and not reinstate it later on that we've completely given up providing any type of email service (whether that be day-to-day email needs or transactional emails). I've spent hours on calls with Microsoft support trying to remedy this and it's just impossible once it happens (and I've had it happen multiple times to multiple IPs and had multiple MS techs confirm this is what is happening)