Before uploading an icon map to the Map Maker Icon, make sure it is the proper size. In fact, 32×32 and 16×16 versions of an icon map are the common sizes.
To activate billing, go to https://console.cloud.google.com/project/_/billing/enable
Learn more at https://developers.google.com/maps/gmp-get-started
Please visit https://developers.google.com/maps/documentation/javascript/get-api-key for further detail on authentication and Google Maps JavaScript API services.
Don’t forget to enable Geocoding API as well as Maps Javascript API to the project in Google Cloud Console and add Geocoding API to API key restrictions as well.