I would like to suggest you go through this Microsoft link: http://answers.microsoft.com/en-us/office/forum/office_365hp-outlook/problems-with-outlook-2013-sharing-calendars/b04e1116-b573-4a1b-b16f-74026b4a6ca5
- Merged by Winnie LiangMicrosoft contingent staff, Moderator 23 minutes ago duplicate
- Merged by Winnie LiangMicrosoft contingent staff, Moderator Monday, May 25, 2015 7:05 AM duplicate
Hi Sue,
Please make sure your mailbox is Exchange account and connected with MAPI instead of POP3/IMAP connection in Outlook client.
Confirm the Calendar folder is owned by you. Then share the Calendar folder in OWA or Outlook Online mode to have a try. If the issue persists, please check the folder permission and set the Calendar permission for other users to have a try.
Regards,