We have a user that needs to have full access to another users calendar to send invitation appointments, appointment updates, ect.
The user that needs this access already has full access permissions and send on behalf permissions to this mailbox.
The user can create new appointments just fine with no problem, however when the user tries to edit existing appointments and send out updates they are getting this bounce back message:
"You can't send a message on behalf of this user unless you have permission to do so. Please make sure you're sending on behalf of the correct sender, or request the necessary permission. If the problem continues, please contact your helpdesk."
As I said, the user already has full access permissions and send on behalf permissions of this persons mailbox.
Thanks in advance for any advice.