Is this an issue with a particular PDF file or with all the PDFs? Please try with a different smaller PDF file and check. If the file is stored in a shared location, please download it to your computer locally and then try again.
Do you get any error messages upon opening the PDF file? If yes, please share the screenshot of the same for a better understanding.
Also, make sure you have the recent version of Acrobat DC(22.1.20169) installed. Go to Help. Check for updates and reboot the computer once.
You may also try to repair the installation from the help menu (Win Only) and check.