Troubleshooting shadow

Hello All..

Does anyone found solution from this problem?

https://www.youtube.com/watch?v=SahuShauZL8

I have been searching for whole week and i can't find the solutions.

please let me know if there is way to clear this problem shadow in vuforia and how you do it.

oh, and i have try with vuforia 6 and there's no change.

Thank's a Lot :D