Just got a xiaomi mi box. Connected to my hisense m3300 55" tv via hdmi. The tv is connected to a budget 2.1 soundbar via optical cable.

I can't seem to get any audio through the soundbar at all. I can get audio via the tv's speakers but nothing else.

I then purchased a toslink cable and connected the mi box directly to the soundbar... Still nothing.

Can anyone suggest what the issue might be?

Prior to buying the mi box, I had a 1st gen fire tv connected to the tv via hdmi with an optical cable connecting the tv to the soundbar and this worked fine (audio passed from the mi box > tv > soundbar).