I give up. If I insert an iframe it works. If I use any other WP instrument (not only yours) it gives me an error: Google API Error: Please include your Google Maps API key in the plugin settings to start using the plugin. An valid API key with Google Maps and Places API access to your website is now required due to recent changes by Google. Getting an API key is free and easy. Learn how to obtain a Google Maps API key
But I did. And it’s the same API that I use for the iframe HTML.