How to startup webcam while playing a unity .exe file

Hi all,

I made a project in Unity that uses a Vuforia ARcamera. It works perfectly when I try it on play mode, but when I export it as an .exe, the webcam is not being recognized. It is just a black screen. But I know that the file is working because I setup some UI panels, and it is showing on the screen.

Does anyone have an idea why this is happening? Please give me some leads if you have any.

Thanks so much!

Mir