Remote

With older legacy cable boxes, when the box received a signal from a remote it acted on that signal directly. I believe digital adapters still work that way. But X1 boxes are different.  When using a remote to control an X1 cable box:

1. The remote sends a signal to the box
2. The box uses an internal modem to send that signal to a server at Comcast and ask for instructions
3. The server at Comcast decides how the box should respond and sends back commands and data
4. The box receives the commands and data and does as instructed

This design means that X1 is very flexible, but more delicate. This chain has many links and if any them are weak or broken, the response to signals from the remote is sluggish, or fails completely. When that happens, if changing the batteries and rebooting the cable box does not correct the problem, you may need to check the coax (or fiber) line and connections.

If the remote still doesn't work properly, you'll probably need to ask Comcast/Xfinity to send out a premise tech to troubleshoot the problem. If the tech finds bad coax, splitters, amplifiers, or connections in your home (even if Comcast/Xfinity originally supplied them) you'll probably have to pay for the visit (approx. $100) unless you happen to have their Service Protection Plan (https://www.xfinity.com/support/articles/service-protection-plan, closed to customers that don't already have it). If the trouble is due to a faulty Comcast rental device or anything outside your home you shouldn't be charged.