Unable to mask a precomp

[arpit26384548xyth]

Whenever i try to create a mask on a precomp layer. It only creates a straight line in the middle of the composition. Mask works when i am applying it on video or text.I have searched all over internet and still cant find a solution. i have reinstalled the software. purged the cache and memory too.

[Mylenium]

Your top layer is scaled to 9% vertically. Of course any mask on it will be squeezed as well.

Mylenium