We were trying this out on a development site and have run into an issue very specifically with the PRO version. Geocode was not successful for the following reason: REQUEST_DENIED. The critical detail is this exact api key works fine in the FREE version of the plugin. We followed instructions, all the requested details are enabled. Why is the PRO not working when the FREE version works?
Google Street View Image API
Google Places API Web Service
Google Maps Geocoding API
Google Maps Directions API
Google Maps Distance Matrix API
Google Maps Geolocation API
Each one is needed for a different purpose in the map.