Many CMS Themes (Wodpress, Joomla, etc) are purchased and come with a non-key version of Google maps which causes errors in the console, and get blocked because they surpass the 25,000 / per day limit or are getting HTTP referrers errors.
That's right, new modern themes are using AJAX deferred api's libraries and there a big difference in requests rate granted by Google
- Google Maps JavaScript API has 25,000 request per day (hip)
- Google Maps Embed API has 2,000,000 request per day (old)
Check for this in your source code -
https://maps.googleapis.com/maps/api/js?sensor=false
So now you are forced to upgrade to get an Google API key, but they certainly make that very easy process.
Head over to Googles Developer Console - https://console.developers.google.com/apis/credentials/ and sign-up.
You want to add Google Maps JavaScript API
Now under Credentials Tab, you be assigned a new API Key, but you have to choose your Accept requests from these HTTP referrers (web sites) to come from your website.
The prescribed *.example.com/* did not work for me! Here's what finally worked;
Now change your code to reflect your new active key, and best practice to add version of library you are using to the URL ?v3
https://maps.googleapis.com/maps/api/js?v3&key={your API key}
and follow this
https://google-developers.appspot.com/maps/documentation/javascript/demos/markers/markers
If you get this then your referrer is set incorrectly, you get a browser pop-up alert with following error:
This page was unable to display a Google Maps element. Please contact the site administrator. If you are the administrator of this site, please check the JavaScript console or check the following page for troubleshooting: http://g.co/mapsJSApiErrors
check your browser console and it will indicate the offending referring URL.
Check this again; and add your website with http(s)://