Cannot change my channel with Comcast remote on tv

I have had this issue ongoing for a while. My modem is working as far as my wifi, I will try to Change channels using Comcast remote snd I get an error message. I still can use my internet and phone just fine. The one channel works just fine. This can part for a few minutes or hours! Any solutions or understanding of why I seem to have signal to watch one channel but cannot change Chanel’s?