In order to maintain high security standards, Trackops locks an account when the wrong password has been entered too many times in a row. Once an account has been locked, the user will no longer be able to access the system until the account has been unlocked by an administrator.
To unlock an account, navigate to a user's profile, and look for the yellow warning block indicating that their account is locked.
To unlock the the account, simply click the unlock this account link, and the user will be able to login again.
If the user is unsure of their password, have them request a new password before attempting to login. If you feel this may have been a malicious attempt to gain access to this user account, it is always best practice to change your account username right away.