Try entering zero. It worked for me - and it's one of the suggestions from the IRS. (Go here and search for "adjusted" and you'll see it: https://www.irs.gov/about-irs/the-2022-tax-season-has-started-tips-to-help-you-file-an-accurate-retu...).
TurboTax told me my AGI was X. My printed return said it was X. The transcript from the IRS that TurboTax recommended getting said my AGI was X. I tried repeatedly and kept getting rejected. But apparently the IRS still hasn't finished processing all the returns from 2020 (even though they cashed my check long ago). So as far as they're concerned, I don't have an AGI for 2020.
I changed my AGI to $0, resubmitted and got the notification that my return had been accepted less than a half-hour later. Good luck!
