So reading responses it appears that if you enter "0" in the AGI field rather than your past year's AGI or your jointly-filed AGI doesn't work the high level of security appears to be highly suspect. In addition, the error message I received did say the spouses AGI or PIN were incorrect. I put our AGI for both. Was mine okay? Talk about finding Waldo. Put in our AGI for me, but "0" for the spouse? Or, maybe the spouses PIN is incorrect, OR maybe whatever is on file is not correct and the answer to e-filing won't be found. Just print and mail in like years before. Is it too much to ask for to have error messages that really guide one to the problem?
If it was rejected for AGI—-be aware that many 2020 returns took so long for the IRS to process that your 2020 AGI might not be in the IRS system. Try using zero instead.
If filing with zero is rejected then file again but select the option that you did not file last year. The IRS does not see that question and it will allow you to e-file with no AGI question.
https://ttlc.intuit.com/community/agi/help/where-do-i-correct-my-agi-in-turbotax-online/00/26311
If that does not work and you still cannot e-file, then print, sign, and mail your tax return.