As from 22/6/2016 it seems that for all new domain you cannot use a google map without any api key!
We tried to move today a website tfrom develop subdomain to a new domain and all the maps was gone!!
But there is a really easy solution for all cms as Joomla, Wordpress, Druplal , Custom etc
So , in order to keep using the plugins that you was using , as bt google map etc, you have to do these steps :
1. Create an api key . please read carefully this link
2. Put this code before </head> in your template
<script async defer src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&callback=initMap"
3. There is always a chance that you plugin loads the googleapis without the api key. In this case your new script must load before the plugin script ( or better delete it from the plugin )