DigitalOcean. They have entire ranges of IP addresses block by some of the blocklist but my users are here in the U.S. and from what I could find those are mos

DigitalOcean. They have entire ranges of IP addresses block by some of the blocklist but my users are here in the U.S. and from what I could find those are mostly used outside the U.S. It's a hit or miss thing. If you spin up a new "Droplet" you should do an IP blacklist check on before your build your server. If it's on more than just a few you might want to start over.