See this TurboTax support FAQ for last year's AGI - https://ttlc.intuit.com/community/agi/help/how-do-i-find-last-year-s-agi/01/25947
To access your current or prior year online tax returns sign onto the TurboTax website with the userID you used to create the account - https://myturbotax.intuit.com/
Scroll down to the bottom of the screen and on the section Your tax returns & documents click on Show. Click on the Year and Click on View adjusted gross income (AGI)
If you filed the 2017 tax return late in the year (November 2018 or later) then enter a 0 (zero) for the 2017 AGI.
If the tax return continues to be rejected by the IRS for the 2017 AGI then you only other option is to print and mail the tax return.
See this TurboTax support FAQ for the procedure to print a tax return for mailing when using the online editions - https://ttlc.intuit.com/community/printing/help/how-do-i-print-and-mail-my-return-in-turbotax-online...
