I will try to do something about it, but I've just about given up with Microsoft these days. Their website for SNDS (the place you go to resolve this stuff with them) is "currently experiencing technical issues" as well, so I can't even start the process of getting it sorted out. The server isn't blacklisted anywhere else on the internet, and yet MS somehow re-blocks it every couple of months, and it takes weeks to get them to remove it. The bottom line is that their system just sweeps up wide IP address ranges anytime there's a spam hit from any of them, and since this is a virtual server in a shared datacenter, I have zero control over who the "neighbors" are and what they do, yet I get caught up in the same net when one of them spams.