Open the page in Chrome, hit the F12 key and then click the Console tab. Google Maps will display an error message here telling you what is wrong. The two most common issues that I’m seeing so far is the referred set in correctly or the APIs not being enabled in the Google API Console.
My suggestion is to look at those errors and correct what Google is saying is wrong. It could be easier to just start over by following the get Google Maps API Keys tutorial.
If you can share a link with me to your directory page, then I can looks to see what the error is and provide more specific advice.
I hope this helps! Let me know.