Vuforia don't working on my Android (UNITY)

Hello,

I have a problem when i build my app on my smartphone.

I have no errors on my consol and the scene work on playmode on my pc with webcam but when i build it on my phone i have camera but no detection of my image ??

I tried on 2 versions of Vuforia and Unity and i have the same issue.

What is wrong ?

I use :

- Unity 2017.2.0f3 with Vuforia 6.5.22

- Unity 5.6.6f2 (and Unity 2017.1.3f1) with Vuforia 6.1.17

- Samsung Galaxy A7 with Android 6.0.1

Thanks by advance !