My Roku Voice Remove Pro has been able to control volume up/down & mute on my Sony soundbar for a long time, but all of a sudden this morning it is no longer able to do so. I tried going through the "set up remote for TV control" again, but no luck. I notice now the setup instructions say that the remote is unable to control soundbars! My Roku system was last updated Nov. 17 to version 10.5.0 (today is Nov, 26) so it seem strange that if the change was due to a system update, it took several days to occur. My player is a Roku Premiere Plus. If Roku TOOK AWAY this ability, I am NOT HAPPY, because this is the main reason I paid for a more expensive remote.
Roku remotes have NEVER controlled audio gear directly, they can only control TV's. It's then up to the tv to control the soundbar via Hdmi-cec. Try refreshing the cec devices in your tv settings.
The fact is, I was able to control the soundbar volume before, and now I am not. I It's not an unreasonable thing to expect, because my Android remote is able to control TVs or soundbars on my Nvidia Android box. This is one more reason why I am using Roku less, and Android more.
I do not have a regular TV, I have a computer monitor and projector, both of which are routed through a Denon receiver. Neither the monitor nor the projector supports audio. The soundbar is connected to the Denon as well, via HDMI.
I can go back to using the soundbar remote to control volume, but it is very annoying to have to switch between the Roku remote and the soundbar remote. Like when I click on a YouTube video that is too loud or too quiet, I have to put down the Roku remote and pick up the soundbar remote to adjust the volume. This is VERY inconvenient.