Menu issues with mobile version

Hi! I’m experiencing problems with the menu on the mobile version.
I have created sub-items and to show them, you need to hoover over the main menu item. The problem is on the mobile version, you have to click on the main menu and when you do, it sends you on the page and doesn’t show you the drop down menu.
Is there a way to fix it?
website is https://www.grayeyesseries.com