There are several work arounds when an AGI does not get accepted when you efile. If you filed an amendment the previous year, then the AGI on the database gets set to zero and you need to use zero to efile.
Another work-around is to say that you did not file taxes the previous year, and that will eliminate the AGI question and allow you to efile.
Adjusted gross income (AGI) is your annual gross income minus certain adjustments that the Internal Revenue Service uses to determine your income tax liability for the year.