Dropdown menu displays behind products

Hello,

I've had an issue with my dropdown menus displaying behind the product pictures.

I honestly have no idea where to begin fixing this.

I use sticky navigation and when the sticky navigation is engaged, I have no problem, but when its at the top of the page and you scroll over the navigation to display the drop down, it displays behind whatever products or post elements are below.

Here is a picture:
https://ibb.co/9GB6Mby