Cant get 5.1 audio output to work

Im running Kodi on an Xiaomi Mi Box. My Monitor doesnt support HDMI so I have a DVI adapter which is working fine for video. My AV receiver supports DD 5.1 (and other sources such as Tivo are playing fine in 5.1). I was only able to get the L R lights to light on the receiver using the optical out on the Mi Box and after doing some searching it looks like others were having the same problem from the optical out.

The Mi Box says that it supports 5.1 audio so I purchased a HDMI audio extractor that says it outputs 5.1 through the toslink port on the extractor. I am getting the same results with or without the extractor.

I have tried all of the audio setting in the Mi Box audio settings (auto, PCM, HDMI, SPDIF)
and tried different things in Kodi under System / Audio (with expert mode enabled).

Im not sure if youtube which I tried as a stand-alone app and also as a Kodi video add-on, even though they say 5.1 audio will really output in 5.1.

I have also tried playing a local 5.1 test file I have through Kodi and while playing it Kodi says it is 5.1 (dont know if that icon above the video scrubber really is accurate or not).

1. I need someone to confirm a true source of 5.1 I can use to test
2. I need a recommendation on the correct Kodi audio settings for 5.1
3. Any ideas or suggestions why I cant get this to work

Thanks