You need the exact 2017 AGI from original return last year. If your AGI that you are entering is indeed correct and you have been rejected and tried all of the steps here E-file reject for AGI or Self-Select PIN doesn't match IRS records, you will need to go ahead and file a paper return (mail it) and get it postmarked before 11:59 PM tonight, April 19, 2018.
AGI is not required on mailed returns. When this happens, for some reason, the IRS has a different AGI in their system. Steps to print and mail can be found here How do I print and mail my return in TurboTax Online?
And if you have been rejected at least 5 times now, you will also need to go ahead and mail the return. The software will automatically reject any e-filed returns after 5. See here When a tax return can't be e-filed no matter what you do