Calendar Sharing Error

The following error message is displayed when trying to Share a Calendar:

If you have previously shared the Calendar with this person, please try the following:

From this person’s Outlook email:

1. Open the Outlook calendar.
2. Click the drop-down arrow to the right of Open Calendar.
3. Select the option to Open Shared Calendar.
4. Enter your username in the dialog box. Click OK.
5. Your shared calendar should now show up in their calendar options.