Your 2018 Adjusted Gross Income is on line 7 of your 2018 form 1040. If you used TurboTax online to prepare and file your return, you can access it using this link: https://ttlc.intuit.com/community/prior-year-return/help/how-do-i-access-my-prior-year-return/00/270...
If you have entered your correct AGI and your return was rejected for that reason, the IRS may not have your correct AGI in their database. You can try entering the number 0 instead of your AGI. That will often work.
