I'm trying to download my 2019 TurboTax-generated tax return file (either as a PDF or the TurboTax file) but having no success. Any suggestions ?

My downloaded 2020 TurboTax program is asking me to upload my 2019 tax return as a PDF, but I was not successful in uploading either the PDF or TurboTax file of my 2019 return, both of which were created by TurboTax.  TurboTax  does not provide an error message, just tells me the upload failed.  Any  suggestions ?