Google forms has changed their restrictions:

Google has changed where the restrictions are in forms.  By default users OUTSIDE of @granitesd will NOT be able to view your forms.  This makes sense for child privacy reasons.  IF you want other people in the world (such as parents, community members, etc.) to access your form you must UNCHECK the “Restrict to users….” Button in the form settings.  This function used to be accessible when you shared the link, but not anymore.