I’m currently setting up GeneratePress on my WP but I encounter an issue with navigation menu on mobile (or on supports below the mobile breakpoint value). When I’m in the customization panel, I see the menu but on mobile or with a reduced browser window, it is not visible :
I see something related to the menu in the code :
But I’m not able to show it. When I increase browser window width, menu appears.
I’ve set 1 menu used as main menu and off canvas menu. I have WP Super Cache, I tried to clean cache and disable the plugin, it didn’t helped.
it looks like you installed the Volume site from the Site Library which uses custom CSS to create the a custom menu. In Customizer > Additional CSS there is a lot of CSS related to the menu this CSS in particular is hiding the mobile menu: