Coordinates should be added here https://gyazo.com/4df01c0fcc364a6cfa128e05b2ac59e6
In “Find Latitude & Longitude” final, you should write location, like New York City. I can see “You need to have google api key for using this option” text that you mentioned. In the browser console:
Google Maps JavaScript API error: RefererNotAllowedMapError
https://developers.google.com/maps/documentation/javascript/error-messages#referer-not-allowed-map-error
Your site URL to be authorized: https://monarrchy.lk/wp-admin/post.php
Regards