You are the only one who has your password, and we cannot reset it. If you do not yet have important files in the vault, and can afford to lose what is stored in the vault, you can start over. Delete the “vault” folder and the "Settings" folder on your drive, and start the application again. The program will reinstall, ask you to create a new password, and will create a new vault.
In most cases, people are unable to log in because either the CAPS LOCK or the NUM LOCK button has been pressed when the password was created, or when login is attempted. You may find a solution by trying various combinations.