Hello,
1. Please try to add this code in Theme Options > Styling > Custom css > Custom CSS for desktop (992px+):
.header-smart-responsive .header-wrapper .menu-wrapper .menu-main-container .menu > li .nav-sublist-dropdown {
top: 0px !important;
}
2. It looks like this code https://prnt.sc/hv328k from your custom css is the reason for the problem. Please try to remove it.
Regards