When logging in, please click on the Complete Steam Account Renewal. This will open a browser window on the Steam site which will allow you to confirm your identity and process the account renewal.
The Steam page to confirm your identity after logging in to Steam looks like this.
Click on the green Sign In button and you will be redirected back to the iRacing login page.
Now, please use your iRacing credentials, email address and password, to log in to iRacing.
Once logged in successfully, go back to the UI and log in there again.