Perhaps check your splitter connection. Or even a failing splitter. Any barrels or wall plates? Not sure where these channels are currently assigned, but they may be high frequencies. What cable was used in your installation. Old cable was usually rg-59. These days rg-6, at least, is recommended.
Thank you for the reply. Connections are fine. I don't know what cables we have but I will check. Problem just started a few weeks ago. The nstallation happended last July. I will call a tech to come out. Just wanted to make certain I wasn't missing something and hoping there was an easy fix.
It turns out the problem had nothing to do with wires or splitters. The Verizon tech was at my house yesterday and the ONT was failing. He replaced part of the ONT and it fixed the problem (finally!). At least I was able to watch the Celtics game last night.
I have a Tellabs ONT. Not sure the model but it's older like the ones in this thread.