Lead Developer
It looks like you have a plugin adding inline CSS to the sub-menus – one of the values is opacity: 0, which is hiding the sub-menu.
Can you try #1 on this page?: https://generatepress.com/knowledgebase/debugging/
If the problem plugin is essential, try this CSS:
.sfHover .sub-menu {
opacity: 1 !important;
}Documentation: http://docs.generatepress.com/
Adding CSS: http://docs.generatepress.com/article/adding-css/
Ongoing Development: https://generatepress.com/ongoing-development