If you have already printed and mailed your tax return, don't efile it. That will just slow things down as the IRS tries to figure out which return is the correct one.
If you have not already printed and mailed your tax return and you want to efile, try using the number 0 for your AGI instead of the actual AGI. If your 2018 tax return was filed late in the year, the IRS often does not have your AGI in their database.
