It happens every time I try to start the game from Steam. Have tried restarting steam as well... (and yes, the new 9,4GB update is installed)
For me aswell. Since I updated to the latest build, always get Error 503 when I try to start the game.
R3E worked fine then I got the "something went wrong screen" and now everytime I try to start I get Error 503
I have that too at the moment... I was in game in a Race, than my PC freezes (my fault because of OC it think) After reboot I got the 503- Message... retried it multiple times in 5min.. maybe to much traffic on servers at the moment
After letting steam verify my game files I get to the same screen as "heretic" posted. After typing in my user/pass the screen stays black for about a minute before I get the same screen as in the first post - but now with a 504 error instead of 503.