Nikon D3200 sound problem?

I bought the wu-1a wireless mobile adapter to be able to send video's and photos to my camera, its fine I can save photos but when I save a video its black and it has a sign on the front, then I go on the app and press " photos on device" ( things I saved) and the video is there but no sound it said error code like it's not compatible?

Anyway to fix this?

I think you totally misunderstand the use of the WU-1a wireless device.

The WU-1a an optional wireless mobile adapter you can use to automatically send images to your smartphone (host) and use your smartphone to remotely capture images from your Nikon 3200.

Note from Nikon website: Movies can't be viewed using the Wireless Mobile Adapter utility (app) but can be played back by tapping the movie or playback icon to display a list of movie apps and choosing an app from the list.

What this all means is that you can only send still images and video from your camera to your smart phone, NOT the other way around. Digital cameras are NOT viewing devices and can't view images from other sources

You need to read the user manual that came with the WU-1a and visit the Nikon website for more information on that unit.