The problem is most likely that Hypptv box.. Some other Android boxes do this as well.. Try this, disconnect the Hypptv box from the TV.. Power off everything else and switch back on.. Except the Hypptv box..you should get sound every time.. Afterwhich, you can switch on the Hypptv.. Sometimes, it works the other way around too. If left connected and in standby, you must switch on Hypptv first, then tv and soundbar or TV, then Hypptv, then soundbar.. Experiment with the different procedures and you'll find the one that works 100% each time.

Your connection is correct. Sony soundbar must be connected to the HDMI-ARC port on the TV, for the HDMI-ARC feature and HDMI-CEC (if supported) to work. The latter might might work regardless of which port.