Sound bars are usually in front of the TV, if its too tall it might be in the way of the IR reaching the TV IR sensor on the front of the TV.
Did it ever control the tv? It has to be programmed to do so, first the wifi remote has to be paired to the Roku, then you pick the brand of tv and follow prompts. It is not going to control your tv right out of the box, they are many brands of tv all using a different IR code set.
Edmund Roku Community Streaming Expert
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