White space on top of header in mobile view?

I have a bug in my website, where a large white space is added above the header/navigation of the site, at a certain breakpoint, however on all other window sizes the menu/navigation works just fine.

Does anyone have a solution to this problem? Ive inspected the site, and havent been able to find where it is in the css that would be adding that extra space.

Please see: https://www.ewdevel.ca/youthhavenbarrie/ if you resize/drag browser width smaller and smaller, you will notice what I am talking about

Any help is greatly appreciated.

Thanks.