Blockify menu blocks header

I am experiencing a problem regarding the sub(sub) menu which is ‘eiwitten’ a little bit lower so that it does not block the view for the rest of the header?

the issue looks like this: https://drive.google.com/file/d/1lhxpIYVlNkLpdq4hz_AvOEuhqtKunpmM/view?usp=sharing

I hope someone can help, thanks in advance!

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