ERROR 500

hi there, im having issues trying to make a change in “customize” generatepress (before i didnt have any error, used to work lovely but now is broken each time i try to make a change in that menu.. )

Also is not a problem for this website, i only work with this theme and all my websites get this error now.

Cannot do anything until i deactivate all plugins, then it works fine… :&

The page I need help with: [log in to see the link]