If your mobile phone has a hotspot feature, connect your roku to it and try it out. It will probably work.

I think that when you set up you Xfinity it looks at & stores your home IP address. The other streaming channels you subscribe to don't care when you are. I had the same problem with Spectrum (Time/Warner) while on vacation. I could stream Spectrum channels to my phone and watch, but when I tried to cast to the TV it wouldn't allow it. At home I was able to cast from the phone to the TV.

Correct, everything works on your mobile devices, but it blocks you from casting that onto a TV. Basically, they don't you to login to your account on someone else's device and give them the ability to watch tv via their services without paying for it. That's why it works on your home network, and not outside of it.

However, the individual apps may work where the xfinity apps do not.

What is a Roku? My TV says Roku, but it's a streaming service, so I don't know what "a Roku" is. It has nothing to do with my phone.

@mtvhike Roku is a streaming service. While they are built into some newer tv's, they also sell stand alone streaming players which is what the op is referring to. More info: https://www.roku.com/

my Roku works away from home. I can take it to work or across country on vacation. Easy peasy but the x app won’t work away from the home network. The individual channels do work fine. I could split hairs and say hbo won’t work using the app but hbo-go works fine away from home

Steve, yes I know Roku is a streaming service, but what is "a Roku"? A TV with Roku written on it? A USB stick with Roku written on it?