Our 2018 tax return has been rejected 3 times for the 2017 AGI. We are entering the AGI from line 21 on our 1040-A 2017 tax return. What do we need to do to fix this?

What is the next step to follow if the taxes are rejected for a 3rd time? I have entered the right AGI from last year return.

That is NOT an answer.  That is another question!

Same question here.

If it continues to reject, then the AGI in the IRS database might be in error. Mail filing is the only option.

See this TurboTax FAQ on how to find your AGI

https://ttlc.intuit.com/replies/3301618

If you filed late last year there is a good chance that the 2017 AGI never was entered into the e-file database. Try using 0 (zero) for the AGI.

If you filed an amended return use the AGI on the first filed tax return.

If it continues to reject then the AGI in the IRS database might be in error. Mail filing is the only option.