I can access HBONOW through old Apple TV devices and through Safari but I cannot access it through the Apple TV app. It states I need to subscribe. I've researched but I'm still unclear as to where the problem is.
Mac Pro
You will have to make a choice, which subscription you want.
If you want to change to the other one, then you should unsubscribe from the former.
The HBO Channel in the Apple TV app requires a different kind of subscription, even though the content is (largely) the same.
To be clear, do I unsubscribe to my current subscription and subscribe under AppleTV? Is so, will I have access to HBO on my phone, laptop, etc.? Or will I now be required to have 2 subscriptions?
And only be able to access thru Apple TV?
I subscribe to HBONOW through iTunes and can watch on safari but Apple TV on my Mac says I need a subscription. what is going on?
