An error 400 is a security error (no permission), meaning your server isn’t accepting data from our Library.
This could be because:
1. Your server is blocking communication with gpsites.co
2. Your server has caching enabled
If it is neither of these, then you might have other security precautions in place on your server. You may need to check with your hosting to see if there’s anything else that might be getting in the way.