Please go to the UI and click Complete Steam Account Creation, as you see below:

Then please use your iRacing credentials, email address and password, to log into the iRacing UI.

If that doesn't allow you to log in, could you please go to on your browser and Click "Log in here" next to "To Log In Via Steam":
If this is still unsuccessful, please log out of Steam completely and then log back into your iRacing account.
Please let us know if this helps or if you are still experiencing the issue so that we can look into your account further. 

Please contact Support at