Can't see why I am not passing

My code works as it should but I can’t see why I am not passing test number 10.

You have put too many links on your menu.
There should only be links to the sections with class="main-section but you have links to the <h3> elements there as well.
They should either be made sections or there should be no links


Exactly. But on your menu there is also links to the h3 level elements, one example is

<h3 id="What_you_should_already_know">What you should already know</h3>

This not have a link or it should be made to a section if you want it to be on the navigation