Menu Item Hover Issue

Hello,

Here’s my issue.

My website is: websterlightgrant.com

I edited my menu bar to eliminate the header space at the top.
However whenever I click on a sub menu item and go to that page, I’m not able to access the drop menu.

I’m only able to access the hover drop down menu when I’m on the homepage.

Furthermore I would also like to eliminate the empty space on the drop down menu.
For example when I hover over About Us, how do i eliminate the space right under the phrase About Us?
How can i fix this?

Thank you!