Since the latest update, Google Maps no longer supports access to their API without a key, because they are introducing paid plans.  You would need to get one for your website in order to make Ventcamp maps to work. The good news is that there are still free plan to use them which is the Standard plan.

First please open up this Google Maps link and click the "Get a key" button

Choose or create a new project

Click "Create/Enable API"

Copy the API key

Paste it into Ventcamp API Integration page and hit Save!