While playing both yesterday and today, I've been DC'd multiple times while trying to change channels. There seems to be no correlation with what channel I change to and when I DC. After DCing, trying to choose my character causes an "unable to connect to the game server" error at first, then a client crash afterwards. Waiting about 5 minutes usually allows me to log back in and start playing. Works fine for a while then CCing causes this all over again.
Try restarting your computer and modem. It's possible some firewall/antivirus program causes connection problem.
I've since restarted my computer and that didn't fix it. Modem has been fine. I'll check my firewall/AV, but they have never given me problems before. Could something have changed if I never mucked with either?
Could be a server problem with your connection, that's why I suggested restarting your modem. Sounds less likely if it started suddenly, those are the only things I know that possibly could help, other than that I guess waiting a day if it stops. Try flushing your DNS http://www.wikihow.com/Flush-DNS
