I've been playing since launch without issues, just woke up and got this error today. Nothing has changed on my end, not sure why this is happening. I've tried repairing but it doesn't help. Any suggestions?

Error: ffff:ffff
Fatal Game Client Exception


This is an error that displays when TERA stops working for an unknown reason. We recommend that you attempt to play again. If the problem persists, please visit FAQ below for additional troubleshooting steps.

http://tera-support.enmasse.com/app/answers/detail/a_id/239

When I got the same error, I switched my default browser to IE since I have no script and a bunch of other restrictions in Firefox (which was my default browser before). I re-started the client and it worked. I had already set the "run as admin" switch.

Not sure if you changed any settings on your browser but if you did, you may want to mess with it and see if it helps you out.