Google Maps on your own domain can require an API key
You can obtain an API key from Google and enter it here, usually a free key is sufficient.
If the map is not appearing, see https://developers.google.com/maps/documentation/javascript/get-api-key See the developer console in your browserfor more information about the map problem, Google will normally display information there about the problem and how to obtain an API key for the mapresolve it.