If you mailed your return or filed later like after August then the AGI might not be in the IRS system to verify you. Try entering 0 for the AGI.
I filed an amended but the AGI is the same
Did you use the AGI from the original return? Use the original AGI.
Filed the amended on Feb 29 2020
YES they were both the same I owed more taxes and paid it
That seems pretty early. Did they accept and process your original return by then? You still use the AGI from the orginal return.