Issue Description

Users that are correctly set up as members of shared mailboxes or delegates with ‘Send As’ rights to user mailboxes in the Portal, are receiving the following message in a non-delivery report when sending from the account in the Outlook Client. Error message as follows:

“This message could not be sent. Try sending the message again later, or contact your network administrator. You do not have the permission to send the message on behalf of the specified user.“

Latest Update and Guidance:

This issue is being investigated under PRB0208829.

The current workarounds are as followed:

• Ensure the following guidance is configured to enable sending mails from the shared mailbox (more specifically the Send mail from the shared mailbox section) – Microsoft KB article

• If the above is unsuccessful and using a later version of Outlook 2212. We would recommend rolling back to this version or earlier.