Audio and video problem with Miracast device

I bought Miracast-enabled device, Microsoft Wireless Display Adapter.

first try, it worked without much pixelation, very rare lag, but sound only on PC, not TV.

second try, same result.

third try, the display/video keeps disconnecting, and still no sound

Does anyone know how to fix this?

I am on Windows 8.1. I have Insignia TV less than 2 yr old.

I tried streaming online TV shows, Youtube videos and personal video/audio files. Same results for all of them.

So it must be my HP PC, not Internet connection/or the adapter itself?