I am using adobe after effect 2015 and I got a black screen in mocha ae after importing MP4 file. I have set the both FPS and resolution as same. Why?

I am using adobe after effect 2015 and when I import MP4 file into the mocha AE it gets black. I set the video and composition FPS as same as well as the resolution and i am using I3 5gen computer and on board GPU. Can u tell what is the reason for that.