Go back into the remote configuration and set it up again. Set it to some tv other than yours by lying to it when it asks to confirm whether you can still hear the audio.
Roku menu path:
"Settings -> Remotes & devices > Remotes"
At this point if your remote has already been setup for the tv but you need to reset it, arrow down to select your Remote (in use).
Now select "Set up remote for TV control" .. And follow the prompts
Roku Community Streaming Expert
I am not a Roku employee, only a user like you. Please, no support questions via private message -- post them publicly to the Community where others may benefit as well.
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Ultra 4800 | Streaming Stick 4K+ 3821 | TCL Roku TV 43S245/C107X