How can I solve the API project authorization error?

If you see the error in the console: "This API project is not authorized to use this API. Please ensure this API is activated in the Google Developers Console", then you should pay attention to the fact that the extension uses the library which works not only with Maps JavaScript API, but also with Places API. You need to be sure that Places API is enabled in Google Cloud Platform to make the extension work correctly. You may check it by going to this page.