Google Query Limit
Google limits the number of address lookups (geocoding). Per day there is a maximum of 2500 requests. This limit is enforced per Internet (IP) address. Since (public) IP addresses may be shared by multiple devices (e.g. on the same WiFi network), the limit may be reached with fewer requests.
If you get the message that the query limit has been reached, it may be, because another user/device has queried google before. You can try to change networks (e.g. 3G instead of WiFi) or just wait until google accepts queries again. The results of successful lookups get cached and those addresses do not need to be queried again.