When this happens you can check the Xfinity My Account app to see if any TV/channel outages have been reported. Single or multiple channel outages can also be a sign of a signal issue that you may be able to fix yourself by making sure that all of our cable connections - at every wall outlet, splitter and box (including your modem) are as tight as you can get them with your fingers. Then try a System Refresh (hit "A" on your voice remote and select System Refresh) to see if that brings it back up.
