PDF Return Import Not Working

I have used TT for years. I started my 2021 return. The program states it can import info from .tax or .pdf files. I browsed for and selected my 2020 pdf file (I no longer have the .tax file). NONE of the info actually imported. I have pretty extensive return, and it's going to be a real pain to re-type all this info! I've never had a problem with this import in the past.