Hi 

I can see the issue on the sticky menu. There are too many menu items to fit in the space provided. If it is possible to restructure the main menu - to have less first level menu items, this would solve the issue. 
This is not the only possible solution though. There are two other things you can do with some CSS. First one is to enlarge the sticky menu width, the other is to reduce the spacing between the menu items. Here are both CSS snippets. Just paste them (one or both) to Theme Options -> Custom CSS:

/* make the sticky menu full width */
@media (min-width: 992px) {
    header.stickymenu .container {
        width: auto!important;
    }
}
/* reduce menu item side spacing */
@media (min-width: 992px) {
    .stickymenu .nav-menu > li > a {
        padding: 6px 7px!important;
    }
}

Let me know if this helped to resolve the issue.

Kind regards,
Andrej