Yes, I did check the IRS site for last year's (2019 return) AGI. It matched the paper return that I filed, and also matched what TurboTax imported from last year's return to my 2020 return. "Incorrect AGI" is a misleading error message. Whatever the problem is, that ain't it. Many other people have the same experience; there is no "correct" entry that will allow your return to be accepted. However, my experience (and other people's) is that entering zero in that field somehow sidesteps that problem.
