If you can't hear TV audio through the soundbar, try the following:
Touch the TV icon on the Bose remote. The system will turn on to the source that was used last, which may not have been the TV
Try a different source connected to the TV or try a media playback service built in to the TV. If the audio can be heard through other TV sources, the issue is with that particular source. Try resetting your TV or connected device to resolve this issue
Some TVs have an audio output setting that needs to be properly configured when its sound is played through other speakers. Check your TV's settings menu for an audio output setting. If one is available, make sure that the setting matches the type of audio connection in use (HDMI ARC or optical) and that the TV speakers are turned off
Make sure that the soundbar’s HDMI cable is inserted into a connector on your TV labelled HDMI eARC or ARC (Audio Return Channel). If your TV does not have an HDMI connector with an eARC or ARC label, use an optical cable to connect the TV to the soundbar. An HDMI input must have ARC (Audio Return Channel) functionality in order for the TV to send its audio to the soundbar.
Reset the soundbar by unplugging its power cable from the power socket, waiting 30 seconds and then firmly plugging the power cable back into a working socket