i've tried the combinations, including using the Master password
Master password should work on all. Try changing the master, see if that works
Changed P/W to Pro series. Tired that for client file. Didn't work.
Reviewed 2019 client file. Used a P/W i remembered which worked. That P/W did not work in 2020.
Not talking about password to open PS, see this link to make you are setting it up correctly.