My Agi is on my last years taxes but I got rejected

When the efile is rejected for AGI, that means that the IRS database amount of your 2019 AGI is not matching what is on your tax forms.  

There are two ways to get around this and efile your taxes.

First, try to efile with zero for the AGI.

If that does not work, then select the option that you did not file taxes last year.  You are just doing that to get the efile option to work.  The answer does not got to the IRS.

The difference in the IRS data could be due to their being behind on processing due to COVID-19.  If you filed an amendment in 2019, that would also reset the AGI amount to zero.