“Your message wasn’t delivered because of security policies.” – Exchange 2007

Today I was forwarded an e-mail non-delivery report (NDR) like this one:

Smith, John Your message wasn’t delivered because of security policies. Microsoft Exchange will not try to redeliver this message for you. Please provide the following diagnostic text to your system administrator.


user@domain.com #550 5.7.1 RESOLVER.RST.NotAuthorized; not authorized ##

The resolution was to grant the appropriate permissions to the user on the mailbox object in Exchange Management Console.  Look up the mailbox and drill down to:

  1. Recipient Configuation
  2. Mailbox
  3. Right click –> Properties
  4. Mail Flow Settings
  5. Message Delivery Restrictions
  6. Add the user receiving the NDR to the list “Only senders in the following list”