Exchange 2010 – “SendAs” bounce back

A client advised me that they have assigned “SendAs” permissions onto a mailbox and when they select “From” field in Outlook, select the user, it works first time and thereafter they keep getting bounce backs. The bounce back error is as follows:


From: Microsoft Outlook
To: Faeem Rahman
Subject: Undeliverable: Test 4


Delivery has failed to these recipients or groups:
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.


Diagnostic information for administrators:

Generating server:
#MSEXCH:MSExchangeIS:/DC=local/DC=xx:MBX61[578:0x000004DC:0x0000001D] #SMTP#


These are some of the remedies we had tried:

  • Updating the Organization Address book
  • Moving the mailbox from one store to another
  • Refreshing the ADPermissions
  • Resetting the ADPermissions

However, the issue still persisted. We then confirmed the version which the client was on. The client had been running Outlook 2016 on one machine and 2013 on another. We verified this was an issue, something from the server side and not on the local Outlook. How did we come to that conclusion?

One of my mailboxes are on the same platform. I created a test mailbox called and assigned my primary mailbox to this test mailbox with “SendAs” rights. But the rights assignment was done through the front-end management portal. I then began running the same tests as the client and received the exact same error. That is how we came to the conclusion, it is something within the Exchange 2010 environment.

After further research, we found many attempts to remediate. However, I combined some of the solutions and this is how we resolve this error.

Assigning “SendAs” Permission to the mailbox

  • Log onto the Exchange Management Console

  • Then proceed to Recipient Configuration > Mailboxes

  • Locate the Mailbox which you would like to add the permission to

  • Double click on the Mailbox or right click and select Properties

  • Select Mailbox Flow > Delivery Options

  • Add the mailbox which you would like to be able to “SendAs

  • You may wonder the “Send on Behalf”. This is still writing the permission on Exchange. Click on “OK” to complete. Then on the users machines, you will be remove the address books completely.

Here is how to remove the Address Book from the local machine:

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