You are probably not in the same account that you used last year.
Many people have multiple TT accounts and forget how to access them. Log out of the account you are in now.
Account recovery
https://myturbotax.intuit.com/account-recovery/
https://ttlc.intuit.com/questions/1901535-forgot-your-turbotax-online-user-id-or-password
Or did you use the desktop version of TurboTax? If so, the files are on your own hard drive or any backup device you used like a flash drive.
https://ttlc.intuit.com/questions/1901486-how-many-turbotax-accounts-do-i-have
https://ttlc.intuit.com/questions/1901535
If your 2020 AGI from line 11 of your 2020 Form 1040 is not working then try using zero.
with regard to turbotax, some taxpayers have multiple accounts, you must be in the account you used for 2020.
try zero for AGI. the IRS was tardy in processing some returns so the AGI on the return was not included in its database. in other situations where the original return was fully processed before 10/15/2021 and you amended at any time, you need to use the AGI off the original return.
in some cases nothing works. you'll have to paper file.