I had to switch ISP and can no longer connect to the game. I may get to the character selection screen, but after selecting a character I am booted back to the logon screen with the message "An error has occurred. Please wait a few minutes and log in again.". There is no error code.

Having read around a little and run tests on my internet connection, I believe this is due to the fact that the game tracks the IP-address you are connecting from. When you load into a new area, the game client makes new connection(s), but the game server only accepts them, if they are from the same IP-address as before, otherwise you get the above, vague error.

The problem is that my new ISP appears to perform some sort of aggressive load balancing. My previous ISP assigned me a public IP-address that, while not static, would remain unchanged for hours or even days at a time. My new ISP appears to use different public IP-addresses for virtually every new TCP connection I make, although they do appear to come from the same /8 range. Another way of putting this is to say my public IP changes constantly.

ZOS, does this sound like a plausible theory? In that case, why are you tracking people's IP-addresses and enforcing such draconian restrictions? Can this be relaxed to be compatible with ISPs, such as mine? I appreciate that I can talk to my ISP or that, very likely, a VPN may fix this problem. However, if there is a solution from the game client / server side, please let me know.