Workbooks is (obviously) an Internet service and you login from the Internet. So protecting your login and data from unauthorised access is an important consideration. One of many techniques that Workbooks uses to protect you is to stop rapidly repeated login attempts with bad passwords. When someone attempts to login to your account with a bad password more than ten times consecutively the system automatically locks the login for fifteen minutes. After those fifteen minutes you can try to login again. Until you enter the right password you will be permitted five attempts before it locks for another fifteen minutes.

So the answer to the question is "just wait 15 minutes and try again". It's likely that you have forgotten your password so you might use the 'Forgotten Password' link on the login screen to reset your password when those fifteen minutes are up rather than just re-entering the wrong password. Alternatively, ask your System Administrator to change your password for you. This will remove the time lock out and you will be given immediate access.