Menu error

I have a problem with my wordpress website where the links in the menu is not working. When clicking on the menu a big black box appears and there is not possible to do anything more. What is wrong and how can I solve this issue?

If you put the right link in instead of going from the menu, there is no problem but I need the menu to work. For example [ redundant link removed ]

The page I need help with: [log in to see the link]