Hamburger menu button not working

Hello,

I’m using the Seafoame theme (a child of Best Reloaded). It uses a bootstrap menu that collapses into a hamburger button at smaller browser widths/mobile.

Early on, the button worked. Then at some point, it stopped working (nothing happens when it is clicked).

I installed the same theme on a different WP install, and the button works, even after adding and activating all of the same plugins.

I compared the contents of the theme’s directory on each install (the working one and the non-working one), and all the files are the same.

I disabled all plugins on the site it isn’t working on, the button still didn’t work.

I created another, simpler alternative menu and that menu had the same problem.

I looked through all of the custom CSS, there was nothing relating to the navbar/hamburger menu.

So I’ve ruled out: the theme, the plugins, the css, the menu items.

What do I look at next?

Thanks for any guidance.