@georgefranciscus There is a possibility that the IRS may not have their 2021 AGI in their database if the 2021 tax return was mailed or if e-filed and it was late in the 2022 year when it was submitted.
You can try entering a 0 (zero) for the 2021 AGI and e-file the 2022 tax return again to see if the IRS accepts the tax return.
