It sounds like a settings issue. Either on the receiver or TV or both. Check that they can pass Dolby signals. It probably won't work on PCM. Some receivers have the option for different sound on various settings. For example the one for TV could be switched off or on a different connection socket than the one you use. For example it might be on optical, or RF, or HDMI.
Make certain that any Blu-Ray player connected is putting out the right signals. Sometimes they can have the option to "mix" signals for certain TV's. This however will kill the signals needed for Atmos.
If there is no power at all, such as no lights at all. Then it has probably had an internal fuse failure, or something has gone in the power supply of the unit.
Some Samsung models can wirelessly connect to each other. You would have to check the manual for your tv and soundbar. Otherwise, the easiest way would be via optical cable.
