Go to the IRS website (irs.gov) and click Get Your Tax Record. If you do not have an IRS sign-in, register as a new user and it will ask a few things to verify you identity. Once in you can immediately download a return transcript and other account records. The transcript compares what the "Computer" or IRS calculated vs. the return as filed. If the IRS changed anything (rounding error, etc.) you will see on the transcript.
I'm having the same problem in the Get Payment application - information does not match. I received a $1 refund check (yes, an actual check) from the IRS after having my refund applied to the 2020 tax year. I do not know if this is causing my issue but TT was off that resulted in the $1 more refund amount. I have tried entering different refund amounts in the IRS website: amount of refund on return, refund amount plus $1, $1 and $0.
Tried again today after the website underwent changes but locked out again. Good luck - maybe your have better result than me.
