When putting a new location into the map I’ve got an error:
“geocode was not successful for the following reason: request_denied”
According to Nathan (WP Google Maps), this was the problem:
“It might have been that the API you created did not enable all the required APIs as the Geocoding API was what was stopping addresses being added correctly”.
APIs are enabled along with your JavaScript API key:
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
Thank you Nathan for helping me out.