Frequently Asked Question
Calendar Sharing: Permission Error when sharing
Last Updated 10 years ago
"I ran into this problem today. The solution turned out to be an email address formatting problem.
If I select the user 's email address that I want to share with from my local contacts list, a list that I created before moving to exchange, then I receive this error message. If I select the user's email address from the Exchange Global list, then I have no problem. Also, entering the address in manually seems to work.
Outlook was autocompleting the addresses for me and using my local contact list. That was causing a problem."
So, try composing/creating a new email message and click on the TO button and find the person(s) you wish to share your calendar with in the Global Address List.

You can also find this issue/cause posted officially by Microsoft here: https://support.microsoft.com/en-us/kb/983062
If I select the user 's email address that I want to share with from my local contacts list, a list that I created before moving to exchange, then I receive this error message. If I select the user's email address from the Exchange Global list, then I have no problem. Also, entering the address in manually seems to work.
Outlook was autocompleting the addresses for me and using my local contact list. That was causing a problem."
So, try composing/creating a new email message and click on the TO button and find the person(s) you wish to share your calendar with in the Global Address List.
You can also find this issue/cause posted officially by Microsoft here: https://support.microsoft.com/en-us/kb/983062