I just started playing the championship and no problems here. Have you tried again? Verified there isn't a "break" from your connection to the R3E servers (run an route scan)?
Tried it a few times over the day. With no success. The Internet and the .exe are connected and running. What do you exactly mean with an route scan?
Every other competition works fine. Singleplayer and testdrive, too.
What I meant was doing a traceroute from your connection to the R3E servers. Check this site out if you don't know how to do it with the command prompt: http://www.monitis.com/traceroute/. It will tell you if there is a "break" somewhere in the connection.
Since everything else is working though, this probably isn't the issue. I'm out of other ideas at the moment since you've done all the tests I would've recommended. Sorry.