Microsoft Exchange Action Could Not be Performed on User

When deleting a mailbox from Microsoft Exchange Server, the following error is sometimes displayed, especially if the user has been an Exchange Administrator:

Microsoft Exchange Error - Action Remove could not be performed on object 'User'
Error: Active Directory operation Failed on User.  This error is not retriable. 
Additional inFormation: Access is denied.  Active directory response: 00000005: 
SecErr: , problem 4003 (INSUFF_ACCESS_RIGHTS), data O
The user has insuFFicient access rights.

Fix:

Open Active Directory Users and Computers

Open the user to be deleted

In the Security tab, give ‘Exchange Servers’ full control

Then, delete the mailbox with the Exchange Management Console or Shell