I found this thread as I'm having the same issue (volume and mute buttons not working) with multiple Roku models on different televisions, Panasonic and Vizio. I did the remote settings fix (IR setup) on the Panasonic and it worked... for five minutes. Then the side buying stopped working again. The Roku's updates are up to date.
If it's a rechargeable battery, make sure it fully charges overnight - that advice was given somewhere in this thread, and I'll be darned if that didn't work for me. My remote has been working flawlessly for me for going on 3 months now. I don't know why a low battery would affect only those 3 buttons, but it seems to be the case. That doesn't explain why I had the same issue with a battery-powered remote previously, even with brand new batteries, but I'm just going to roll with it.
I realized by your response this is a thread specifically for rechargeable remotes.None of my remotes are rechargeable, they are all battery powered. Maybe I should go see if there's a thread for that. However, the issue is exactly the same.
Warm greetings here in the Roku Community, @ejeichelberger.
Thank you for informing us about the issues you've encountered with the mute and volume buttons on your remote not working. No worries! We'd be happy to find you the best resolution for this.
Could you please confirm if this is the remote that came with your recently activated Roku Streaming Stick 4K? If so, does resetting it help? To reset, press and hold the Back and Home buttons simultaneously for about 20 seconds and pair them again.
We'll be anticipating your response!
Best regards,
Carly