Users who are wanting to share their calendar to others in our organization are doing the Following...

1. Going to the Properties of the calendar

2. Selecting the Permissions Tab.

3. Adding the user they want to grant permissions and granting the appropriate rights.

This works fine if outlook 2010, but when a user tries this in outlook 2013, a message pops up saying:

An error occurred when setting schedule permissions. You don't have appropriate permission to perform this operation.

When the user goes back to the properties of the calendar, they see the user they have added with the correct rights. But the users who was given rights to the calendar still can't create events on that shared calendar.

Again, doing these steps in outlook 2010 works perfect.

Does anyone out there know what may be causing this?