Lookup for "214 4.5.4"
Temporary Error - This status code indicates a transient issue and may resolve itself.
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 (4.5.4)
Invalid command arguments
A valid mail transaction protocol command was issued with invalid arguments, either because the arguments were out of range or represented unrecognized features. This is useful only as a permanent error.