How can I obtain the AGI for 2021? That is what is holding up my return.

Do you mean your 2020 AGI so that you can e-file your 2021 return?

Where do I find my AGI?

https://ttlc.intuit.com/community/agi/help/how-do-i-find-last-year-s-agi/01/25947

https://ttlc.intuit.com/community/prior-year-return/help/how-do-i-access-my-prior-year-return/00/27010/message-id/746

Your 2020 tax return shows your 2020 Adjusted Gross Income  (AGI)  If you filed a joint return then the AGI is the same for each of you.

Form 1040        line 11

If you are using the same TT account that you used last year, you should also be able to find this number in your Tax Home for 2020

If entering the amount from your 2020 tax return does not work, then try entering “0” instead.  If that does not work and you still cannot e-file, then print, sign, and mail your tax return.

You can get a free transcript of your past return from the IRS:  

https://www.irs.gov/individuals/get-transcript

Note: If you filed late or amended your return, your correct 2020 AGI may not be in the system. 

https://ttlc.intuit.com/questions/1944348-how-do-i-print-and-mail-my-return-in-turbotax-online