There was a Gmail outage https://www.google.com/appsstatus#hl=en&v=issue&sid=1&iid=42ac36fa05acb358c21dfbce7e105bb8 and Google Calendar outage https://www.google.com/appsstatus#hl=en&v=issue&sid=2&iid=42ac36fa05acb358c21dfbce7e105bb8 that caused this incident.