Hamburger menu on mobile does not work, as it is a “open on hover” on desktop with a mouse, it does not do anything on Mobile.
It seems “open on hover” on mobile too, but as you know, there are no mouse cursor on touchscreens.
How can open up the menu on mobile?
I suggest setting the popup to open on click rather than on hover, as this is a more intuitive behavior for visitors. You can also enable it to open on click even if it already opens on hover, so that it works properly on mobile devices.
Alternatively, you can create two separate buttons, one for desktop that opens the popup on hover, and another for mobile that opens it on click. Then simply hide the unnecessary button on each device by unchecking “Show on this device” in the Arrange panel.