SurroundBar 6000: Sync button not working

My SurroundBar 6000 is not syncing when I turn both the bar and the subwoofer on. The subwoofer flashes green slowly. So, following the directions, I turn off the subwoofer and then press and hold "Sync" on the back of the sound bar. At this point, my understanding is that the LED on the back of the bar (next to the "Sync" button) should start blinking. This does not occur. Any thoughts on what might be happening? Thank you!

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