Lookup for "214 2.1.6"
This status code indicates a successful delivery or other operation. Any details are simply notes.
Basic Status Code Details (214)
Help message [Information on how to use the receiver or the meaning of a particular non-standard command; this reply is useful only to the human user]
Enhanced Status Code Details (2.1.6)
Destination mailbox has moved, No forwarding address
The mailbox address provided was at one time valid, but mail is no longer being accepted for that address. This code is only useful for permanent failures.