Fingerprint works but not password
I have a password-protected file on my Mac (Ventura 13.4). It is in DropBox. My fingerprint will open it but my password will not. The password I am trying is my Mac login password. I am sure it is correct because I log out and in again to test it. My caps lock is not on. I open the KeychainAccess app, find the file in question, click 'info', and select the 'show password' check box. It asks me for a password. I enter my Mac login password. It then asks me for a password again. I enter my Mac login password again. It then shows nothing in the password field - it is just blank. I need the password because I want to access the (Dropbox stored) file from my phone and my phone asks for the password. It seems the fingerprint mechanism knows the password, but I cannot get it to tell me what it is.
MacBook Air 13″, macOS 13.4