Vray animation get darkess

[josem1]

I am using Vray 3.00.07 and 23s max 2015.

 

I am rendering an exterior building. Testing the sequences in difference part of the animation give me perfect result. But when I run the animation the image get darkest.

For example, running for frame 0-500, the 300 is very dark. But if I start render from 300, get lighter. I am rendering with Brute force as Primary engine and secondary engine.

 

Please, some ideas how to solve it?

 

Thanks