Please read how to get API key https://developers.google.com/maps/documentation/javascript/tutorials/adding-a-google-map#step_3_get_an_api_key .
Then you need edit the file wp-content/themes/blanco/code/shortcodes.php, find the line wp_enqueue_script('google.maps', 'http://maps.google.com/maps/api/js?sensor=false');, replace the code with this http://maps.google.com/maps/api/js?key=YOUR_API_KEY&sensor=false');, add your API key instead of “YOUR_API_KEY” text in the link.
