site scrolls left on mobile devices

Hi

I’ve installed A2017 and all seems to work fine BUT the page swipes left on mobile devices leaving about 150px dead space on the right side – NOT GOOD! Also you can see a scroll bar showing this in WP Admin when selecting mobile view – it shows up in Chrome but not in Firefox. I’ve tried everything and it doesn’t appear to be connected to the size of header image – more like a container problem. What is going on here please and do you have a fix?

Ricardo