I am very happy to report that I tried this solution and it worked! I tried repeatedly to file my 2020 returns and kept receiving the very same error message. I double checked all of the information from my 2019 returns, I tried re-entering information but nothing worked. I had at least 10 rejections before I decided to look up my problem on these boards and see if I could find some help. I did! I entered the "0" as recommended for the 2019 AGI and the returns were accepted within 5 minutes!
Thank you!
