Code Highlighting stopped working

Hi, I use WP Editor on all of my sites, tried even to deactivate all plugins. In the wp plugins folder there’s no naming problem like duplicates and stuff. This feels obscure to me, tried to reinstall several times under different conditions, no luck. Can it depend on with a problem with ajax? The website I’m working on has apparently a problem with ajax loading that doesn’t make me save Visual Composer design settings.