Hi there,
There are a few steps you can take to troubleshoot your Soundbar.
Please verify that you are running the latest firmware on your Soundbar. You can download the firmware directly from Samsung’s website by clicking “Support” in the top right corner. Then go to “Manuals & Software” > “TVs & Home Theater” > “Home Theater” > “Sound Bars”. From there, you can select the HW-Q990C under Q-Series.
Alternatively, you can setup your Soundbar using Wi-Fi with the SmartThings app. This will allow you to set the Soundbar to automatically stay up to date for all future firmware releases.
Try doing a soft reset, unplug the soundbar from the outlet for roughly 30 seconds and then plug it back in.
If this still does not correct your issue, then do a hard reset. With the Soundbar on, press the + & - Volume buttons on the body of the soundbar at the same time for at least 5 seconds. INIT OK” appears on the display and then the Soundbar is reset.
~Samsung Solutions