If nothing else you've tried so far works, give the remote the ol' factory reset. However ... If you have the Xfinity Voice Remote XR15, the method is slightly different. If you have the Xfinity ...
The XR16 works with a Flex TV Box provided by Xfinity, so you need the box and your TV to make the remote work. When you complete this process, your remote can control your TV. The XR15 works with ...