Auto Exposure for mobile.

Hi,

I have successfully built my game ( Interior Scene for ArchViz ) for Android platform .apk .
Targeted hardware : Mobile / Tablets , Maximum Quality ( Tried Scalable 2D/3D as well )
Test Phone : Motorola G4 Plus ( Qualcomm MSM8952 Snapdragon 617, Adreno 405 GPU, Android N )

But When I run the game in my phone, the Auto Exposure is disabled and the scene looks dark. How can I fix this?
And if the AutoExposure is not supported on Mobile platforms, then is there a workaround for this?
Please help.