Error Message

Error message displayed for the queued messages, "400 4.4.7 The server responded with: 550 Requested action not taken: mailbox unavailable. The failure was replaced by a retry response because the message was marked for retry if rejected"

The error "550 Requested action not taken: mailbox unavailable. " is not an SMTP code returned by our SMTP servers.  This specific error is related to firewall or SMTP Proxy where the proxy MTA handles the mail transfer.

The solution is to configure the firewall with SMTP proxy to allow all traffic to the Veritas Alta Archiving journaling address domain. Given the wide variety of hardware and software firewalls please consult the firewall vendor for specifics on completing these steps.

Emails addressed to the Veritas Alta Archiving journaling email address queue up on Exchange with this specific error.
"400 4.4.7 The server responded with: 550 Requested action not taken: mailbox unavailable. The failure was replaced by a retry response because the message was marked for retry if rejected."
This behavior is highlighted by only some of the messages returning this error. Typically these messages will be from external senders (inbound emails).