I cannot delete this appointment reminder that was sent to me from Joe Cooper Ford when making a service appointment. Keeps popping up, over and over. I cannot edit, delete, change, there is no "read only" option as recommended below. This appointment does not show on the calendar either so I cannot right click as also recommended below. This is very annoying. Status Code: 2,147,500,037, null Server Replied with 400 If you're seeing this message after snoozing or dismissing a reminder and this is for a calendar you do not want to add or edit events for, you can mark this calendar as read-only to avoid such experience in future. To do so, get to the calendar properties by right-clicking on this calendar in the list in the calendar or task view.