Watch Xfinity TV shows on Apple TV

I can use AppleTV to watch most channel I usually watch including my Xfinity cable plan, like ABC, NBC, AMC, HBOgo. I start with AppleTV 3 in 2015. It worked fine. Now I'm using a New AppleTV. It's a little bit different from the last generation. You need to add the channels by yourself from AppStore. The channel App you download must included in your cable plan. After install the channel App, you need to activate it online then you can stream the show on your AppleTV. For example, you have HBOGO in your cable plan, so you download and install the HBOGO App. At the first time you open the App, it ask you to login, it'll show a code on your screen. You need to grab your iPhone, iPad of laptop to go to the URL www.hbogo.com/activate/ , then choose device/AppleTV, cable provider/ Comcast Xfinity , enter the code, then you need to login with your Comcast account. If you lucky, you can stream HBO show on your AppleTV. Because recently I found the channel App often logout automatically. When I try to login again, sometimes it's not work. When I run the activate process, it will lead me to a page says: "this network is not included in your current Xfinity TV service " I don't know why, but it happens occasionally. I called the support, they said it's network problem and will transfer the call to a special line to fix it.

What a disappointment. All I'm looking for is to be able to watch my recordings on a larger screen than my iPhone when I'm away on vacation.  

12/4/17:  Trying to use my iPad Air 2 and Apple TV 4K, for that I find that this is prohibited by the Xfinity Stream TV iOS app.  (Of course,  because if the app was available on Apple TV or I could just stream from my phone, then why would I pay $n.nn / month to rent my X1 cable box?  Think of the upset to the entire Xfinity X1 business model if some app deprecated the use of a cable box.).   Why doesn’t Xfinity just make this work, but force me to pay a monthly subscription for the app allowing me to be billed on my cable bill?  I do not know.  It is possible to screen mirror the guide, but as soon as you select a program it throws an error message saying that it’s not allowed.

I was told by a Comcast employee that Apple TV COULD stream the Xfinity app and allow us to replace our cable box. What a waste of money! I guess I now double-down and have to buy a Roku and see if that works?? Sheesh!