1-Log in to your iTunes account through iTunes on your MAC or PC.
2-Select Store from top and then view account, put your iTunes password again.
3-Move down until you see Settings under that you will see subscriptions select manage.
4-You will see HBO NOW with Auto renew on, select edit then select Auto renew off then done.
5-Download HBO NOW App for your iPhone or iPad and register with your same Email what you are using for Apple itunes, BUT different Password.
6-Go to your Apple TV and select HBO NOW and select second option, which is you have an account and subscription.
7-It will ask for your Email and password, put the Email and password you created in step 5.
8-Do the step 1,2,3 and 4 but change HBO NOW with Auto renew to ON then done.