CycleGAN for photo to monet

I tried implementing CycleGAN for image to image conversion of photo images to monet style images for a kaggle competition.
But everytime it is generating the same images and those images are all gray.
like this :point_down:

I am not getting what mistake have i done.
Please guide me how to correct this.

This is a link to my notebook :point_right: cyclegan_notebook