Visual Composer is one of the best drag and drop page builder plugin. Whenever you cannot edit things both at front-end and back-end editor, please follow the below steps to fix the errors and get it running as it should.

STEP 1: Enable Visual Composer

• In WP admin panel, navigate to Visual Composer > Role Manager
• Choose Post Types tab and mark all tick boxes

STEP 2: Create an google map API key

Because there are some JS conflicts between Visual composer and Google maps Javascript, you need to create an google map API key

• Access here to get an API key
• In WP admin panel, navigate to Theme Setting > General > Map google API Key
• Input the key you have just created