Google maps API referrer not allowed

Note the DOT at the beginning of the expression, it's a char!

*.stackoverflow.com/* // this will not work with http://stackoverflow.com and will allow for domains such as demo.stackoverflow.com

Replace above with:

*://stackoverflow.com/* // now it will cover all domain variation but not subdomains.

Try to add all type of urls like:

http://stackoverflow.com/*

http://www.stackoverflow.com/*

*.stackoverflow.com/*

Definitely it will work.

Recreating the API key at console.developers.google.com fixed the issue for me.