As the mouse doesn`t change its appearance, hovering over 4-5 and 6 and further down, I pretty much assume that something is covering those buttons?
yes the menu covers it... drop down a breakpoint and you see the menu is now behind his scroll script so 4-5 and 6 work again
also just fyi that Nordvesten terrasse link is the cause of his permission error... different issue but worth fixing
How do i fix the other problem?
I would try removing the animated bounce as my first step
Is there any way I can solve the problem with the menu? I would like to have this menu on the page.
Be aware, that layers are necessarily working site-wide, not page-wide.
Your menu issue is already checked to be solved? If there are any other issues, provide us with some more details or open a new thread as this one is checked to be solved.