We had players reporting on being unable to connect across a wide range of servers. After troubleshooting with players in trying to replicate, we found that the issue seemed to not share similarities save that the majority of players reporting issues came Europe.

The issue was identified in that one of the European ISPs began using IPs which were previously set aside as unusable and thus were filtered for spoofing/security purposes. Now that those IPs are usable by the general public, that filter has been removed.

Thanks to the players who reported and assisted via Helpspot in addressing this issue.