Safe mode is a really useful way of tracking to see if it’s a custom theme component or plugin having an effect. https://theusamarket.com/safe-mode
I see the same as @agungor, the hamburger menu on the top right functions as expected, but the extra one in the top left does not work and only gives a blank pop-out. Is the intention to have two hamburger menus?