I assume this is for a single filer, since you didn't mention it being a joint return.
For the 2019 AGI, be sure you are using the figure from your original 2019 return, not an amended one.
The AGI is on the 2019 Form 1040, Line 8b.
If your return was filed real late in the year, such as after mid-November 2020, try an AGI of 0 (zero).
Or if your return was delayed in IRS processing for several months and wasn't fully processed by mid-November, try an AGI of 0 (zero.)
If you qualify to open an IRS account, you could download a 2019 tax return transcript at the IRS website to see what they are showing for your 2019 AGI.
In any case, before giving up always try an AGI of 0 (zero) just in case--sort of like a "Hail Mary" pass in football.
