My site is not 100% responsive design

Hello. I am writing because my site is not 100% Responsive design.

Parts of the pages you’ve created are responsive but not others.

URL: http://www.iglesiacristianacuadrangular.org

I have done tests with test sites for responsive and everything goes well, but I have tried with my phone Motorola X and goes as you can see in the pictures. A white stripe to the right.

SCREENSHOT 1:

SCREENSHOT 2:

In most every page goes this strip, except in the registration section, the yellow background (as you can see in the picture). Yes there fits perfectly to the resolution.

What I can do to fix it? Thank you very much.