How to Fix a Roku Remote Volume Not working (Visual guide)
If the Roku Remote volume is not working, pair the remote again by taking the batteries out and hold the pairing button. If your remote model does not have a pairing button, then navigate to settings > Remotes & Devices > set up remote for TV control. Next, restart the device by pressing Home (5x) > Up > Rewind (2x) > Fast forward (2x).