If you experience connectivity issues - such as disconnects, problems with connection to the game server, or problems while accessing certain game modes, it is worth checking whether you have all ports used by the game open.

TCP Port 5020
UDP Ports 20000 through 32000

Also, here is a list of server addresses, in case you wish to self-diagnose some situation with a particular server via command prompt commands (pathping, ping, tracert, etc.), or just measure your latency values to any of them:

Server	default.live.d1.gmru.net
Europe	amsterdam.ping.d1.gmru.net
North America	dallas.ping.d1.gmru.net
North America	washington.ping.d1.gmru.net

For instructions on how to forward ports, please contact either your ISP (Internet Service Provider) or manufacturer of your modem/router.