Because the Google Geocoding API has the following limits in place:
Users of the free API:
Google Maps API for Work customers:
Google Maps API for Work cost (today January 2015): 11'000$ / year. There is no other option.
You have probably a 'shared' hosting. And the quotas is used by another site on the same server. See next faq
A solution can be to change the Geocode Factory setting to Client side geocode, after you have used the server quota, then you should be able to do 5000 geocodes / day. Not sure this is allowed from google...
From the Geocode Factory control panel, go to component settings, Geocode tab, and enable the client/server geocode option.
This can be due because you are using an non registered google API key. Please remove the commercial API key from the component settings. If the issue presist, please enable the component debug mode, and open a ticket.