It looks like you’re missing some code according to the ACF docs – see example under “Required CSS & JS” – http://www.advancedcustomfields.com/resources/google-map/
Sadly – this page of the ACF documentation may be out of date. According to google maps API docs – you’ll need to create an API key for all their APIs (Embed, JS, etc)
For more info please visit – https://developers.google.com/maps/