Fingerprint lock in doesn't show up and shows master password instead

I had been using fingerprint log-in since day one for 4, 5 yrs. Today i launch the app and it did not show the fingerprint lock in and it shows Enter Master Password.

I tried few passwords that i used previously but all didn’t work. Now i left with last try.

If i select forgot password, the app shows “Unfortunately, you’re the only one who knows your Master Password…”

What option do i have? How do I make the fingerprint lock in appear again. All my other apps that use fingerprint log-in have not issue, so it can’t be my fingerprint scanner fault.