A User's account will become locked when they enter a password incorrectly 5 times or more.
To unlock the account, first locate the user and click on their Username to enter the administration area. See the guide View Users if you are not sure how to locate a User.
Scroll down the page until you can see the Actions toolbox.
Click on the Unlock Account link.
The popup window will confirm if the account is locked.
Click on the Unlock button.
The account will be unlocked.