LG Media Player Audio Format Problem

I just purchased a new LG TV and also purchased the $30 Network Media Player (SP520) they sell. Didn't expect much for $30 but figured I would see what it can do. It won't read my BR iso files, doesn't even see them, shows an empty folder. It sees MKV but when I tried to play a BR MKV file made with MakeMKV it gives me a "unsupported audio format" message and does not play.

Does anyone have this device and know what the problem is, what audio format I need to use for audio?

Thanks