When trying to file an amended return TurboTax returns with a failed validation advising that an update needs to happen but subsequently tells me my software is up to date. I do this a few times and restart TT with no improvement.
What tax year did you amend? If it is a past year, like 2020 or 2021, you cannot e-file it. You have to print, sign and mail it.
Only certain paid tax pros can still e-file past year amended returns. You cannot e-file an amended return that you prepared yourself using TurboTax. Your 1040X must be printed, signed and dated in ink, and then you need to mail it in. Use a mailing service like certified mail so you will know the IRS received it, since you will have a long wait for it to be processed.
You can watch for information here:
https://www.irs.gov/Filing/Individuals/Amended-Returns-(Form-1040-X)/Wheres-My-Amended-Return-1