To configure your maps API, log into https://console.developers.google.com.
From the "Enabled API's & Services" screen choose "+ ENABLE APIS AND SERVICES" from the top of the screen.
Now click on CREDENTIALS from the left hand menu.
Next, click the CREATE CREDENTIALS link atop the screen and choose "API Key"
Once created, click the API Key 1 link:
In the configuration screen for the key, name your key "Map API Key" or something similar so you can track it later. Follow the guidance below to ensure that your key is restricted to your site.
HINT: in the referrer restriction box, enter your domain and add "/*" to the end. This is a wildcard which allows any page on your site to display maps (vs just the home page).
Ensure that both the Maps and Places API's are in the key definition under "API Restrictions > Selected API's"
SAVE! Now, just click the "SHOW KEY" link and you can copy it. Return to your OwnTheCrowd admin console and paste the API key!
If your map still doesn't work, or if it works for a time and then stops, check this article from Google: