Can't control sound volume

Hello,I have a chromecast device that I wanted to connect to a PC monitor. Unfortunately, this PC monitor does not have any speaker, so I bought this device to use external speakers.Works great, except that the sound control from my smartphone does not do anything.Any idea?

Hello,

I have a chromecast device that I wanted to connect to a PC monitor. Unfortunately, this PC monitor does not have any speaker, so I bought this device to use external speakers.

Works great, except that the sound control from my smartphone does not do anything.

Any idea?

http://ift.tt/eA8V8J