Several users are having that issue with the IP PIN section tonight.
If you are using desktop software, you can also enter the 6-digit IP PIN in Forms Mode on the Federal Information Worksheet, Part VII. Go to Forms Mode, and in the left column forms list choose "Info Wks". That should be the Federal Information Worksheet. Scroll down to Part VII, and the IP PIN should be the first item in that part of the worksheet. Please report back if that worked for you.
