Cannot add users into Send On Behalf - Grant this permission to in Mailbox Properties \Mail Flow Settings tab \Delivery Options.

We have a single Exchange 2010 on premises. When we tried to add a user (say user1 or other users) into "Send on behalf - Grant this permission to:" in a mailbox (say user2) (Properties \ Mail Flow Settings tab \Delivery Options \ Send On Behalf - Grant this permission to)  we got an error telling me that a user (say user99) cannot be found. That user99 is a former employee still with a valid AD account but doesn't have a mailbox anymore. What could be wrong?
Here is the error:
-------------------------------
The following error(s) occurred while saving changes:

Set-Mailbox
Failed
Error:
Couldn't find object "ourdomain.com/ou/Users/Cleveland/Marketing/user99". Please make sure that it was spelled correctly or specify a different object. Reason: The recipient ourdomain.com/ou/Users/Cleveland/Marketing/user99 isn't the expected type.
--------------
I did try to add this same user (user1) to "Send on behalf" in other user's mailbox than user2 and found no problem. It seems like the user2 mailbox is corrupt, right? How to fix this issue?
CastlewoodAsked:
Who is Participating?
 
FOXConnect With a Mentor Active Directory/Exchange EngineerCommented:
Let's try it with exchange management shell

set-mailbox ‘mailboxnameinquestion’ –Grantsendonbehalfto 'emailaddress'
0
 
CastlewoodAuthor Commented:
set-mailbox 'info' -grantsendonbehalfto 'fname lname'
0
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

All Courses

From novice to tech pro — start learning today.