“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.


[email protected] #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”