1) double-check the file extension...is it ".pdf" ? or ".txt' ? (IF it's ".txt", you can change it to ".pdf" , and it might work, but that depends on whether it's already messed up or not)
2) if you used the "Edge" browser to download the PDF, try using a different browser to download it...and try again.
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*