Steam API is currently reporting outdated information to our servers, therefore some users can't register in TruckersMP. There is nothing we can do since it is not a problem on our side. If you experience that, please try again later. Sorry for the inconvenience.
We are also aware of the recent ATS game update and that it is not compatible with the mod. Our devs are working to get the mod compatible again as soon as possible. To downgrade your game and play ATS click here. ETS2 is still working!