Cause: The CAPS LOCK key is on
Solution: Make sure that the CAPS LOCK key is turned off
Passwords are case-sensitive. They must be typed with the same combination of uppercase and lowercase letters that were used to create the password.
Cause: The password was misplaced or forgotten
Solution: Passwords cannot be reset or recovered if lost
Unfortunately, if you’ve misplaced or forgotten a password for an Office application, there is no way for Microsoft to recover it. Microsoft doesn’t store these passwords. There are some third-party solutions for cracking a password-protected file, but these programs haven’t been approved or tested by Microsoft. If you choose to use one of these methods to recover a password, please be sure to back up your files first (and understand that you do so at your own risk).