If you filed by mail last year, try a zero for last year's AGI
Did you e-File with TurboTax last year and import your prior return?
Did you make a note of the PIN you invented last time?
Select file by PIN instead of by AGI.
See this TurboTax FAQ on how to find your 2016 AGI
https://ttlc.intuit.com/replies/3301618
If you filed late last year there is a good chance that the 2016 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.
[The IRS past year AGI identification method has always been unreliable which is why they came up with the electronic filing PIN that worked much better than the AGI. That is no longer an option after ID thieves figured out how to hack it so the IRS got rid of it, now we are back to the old and unreliable AGI method.]
If the E-file rejects with error IND-163:
Return already rejected multiple times for AGI or self-select PIN. You can no longer e-file using these methods, print and mail your return instead.
https://ttlc.intuit.com/replies/6501369