PDF of Turbotax 2021 Will not Upload

I am trying to import a PDF of my 2021 return. I can't use the actual TurboTax TAX file as I seem to have made small updates before printing and I did NOT save those updates to the TAX file. 

 

When I select the PDF it says "The import was not successful" and doesn't offer any error.

 

This is frustrating as I need to amend the return, and before I can do that I need to have the correct information from the original...