Copied from my reddit post:

This is an odd problem I've never encountered before with any game or program that needs an internet connection. Basically, PSO2 tells me there is a 630 error (lost connection to server, timeout) after roughly 15-20 minutes of playtime. Every goddamn time. It happened five times in a row now with similar timeframes until the error message occurs and it only happens when PSO2 is running.

The odd thing is that it doesn't kill my whole internet connection, but the connection between my WNIC (one of those USB dongle thingies) and the router. I allowed both the launcher and the pso2.exe connection through my firewall but it didn't help. Seems like the router somehow fails to assign an IP to my PC after PSO2 runs for about 20 minutes. I don't know if this is a client or a system issue. I'm not a network expert. I'm just stumped.

If anyone encountered something like this before (not just with PSO2) or has a solution, let me know. I haven't tried reinstalling it yet. That will be next.

I'm using a 64-bit Windows 7 and Windows Firewall.