If you get continual lockouts after changing your Active Directory password, there are several possible reasons. Two of the most common are using other devices to access your email and stored passwords in the credential manager of windows.
Windows Credential Manager
Suffice it to say that you need to put ALL devices (phones, tablets, laptops, computers, etc) that use your Active Directory credentials in any way (email, wireless, etc) either on airplane mode or turned off completely. iPhones will ask for the new password when they come off airplane mode, if you are using the built-in email program. Android phones will do the same depending on the email program you use. The “best” way to be sure nothing will lock you out after changing your password is to have each device delete the email account (exchange email is kept on the server anyway), and not be connected to the network/wireless until you are finished changing the password. This includes any machines that may connect to Active Directory from home.