ID Vault password only work periodically

I couple of weeks ago, I tried to log into my ID safe that was told that the password was incorrect. When I looked on line I understood that I would have to delete the ID Safe and start over. I put that off for about a week and then gave it one last try before deleting the ID Safe. the password and I have been using it since. Today I tried to access the ID Safe again and now again it says that the password is incorrect. I displayed the password as I typed it so I know that I got it correct. What might be causing this?