My return was not accepted because of my 2019 AGI. The AGI that was submitted was exactly what was on line 8b if that's not correct why was it accepted last year?

I am having the exact same problem,  Don't know what is going on.

Here's a help article if your return was rejected. There's a heading: My AGI is correct, but I still get rejected with IND-031 or -032.

Follow the instructions listed there.

The AGI or Self-select PIN from last year doesn't match IRS records