Lookup for "214 2.7.9"
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 (2.7.9)
Authentication mechanism is too weak
The selected authentication mechanism is weaker than the server policy permits. Client should retry with a new authentication mechanism.