Internal server error message
I'm guessing you're using some sort of Google Maps plugin on your site. Google recently started limiting access to their Maps API, and now you need a key to be able to make Maps requests.

Go here to request an API key: https://developers.google.com/maps/documentation/javascript/get-api-key. Then input the key into whatever plugin is using Google Maps. There should be a field in the plugin settings that asks for the key.