[
[["smtp 1xx"],["indicates the mail server has accepted the command, but does not yet take any action. A confirmation message is required."]],
[["smtp 2xx"],["Mail server has completed the task successfully without errors"]],
[["smtp 211"],["System status, or system help reply"]],
[["smtp 214"],["Help message"]],
[["smtp 220"],["<domain> Service ready"]],
[["smtp 221"],["<domain> Service closing transmission channel"]],
[["smtp 250"],["Requested mail action okay, completed"]],
[["smtp 251"],["User not local; will forward to <forward-path>"]],
[["smtp 252"],["Cannot VRFY user, but will accept message and attempt"]],
[["smtp 3xx"],["indicates the mail server has understood the request, but requires further information to complete it"]],
[["smtp 354"],["Start mail input; end with <CRLF>.<CRLF>"]],
[["smtp 4xx"],["indicates the mail server has encountered a temporary failure. If the command is repeated without any change, it might be completed. Try again, it may help!"]],
[["smtp 421"],["<domain> Service not available, closing transmission channel"]],
[["smtp 450"],["Requested mail action not taken: mailbox unavailable"]],
[["smtp 451"],["Requested action aborted: local error in processing"]],
[["smtp 452"],["Requested action not taken: insufficient system storage"]],
[["smtp 454"],["TLS not available due to temporary reason"]],
[["smtp 5xx"],["indicates the mail server has encountered a fatal error. Your request can't be processed"]],
[["smtp 500"],["Syntax error, command unrecognized"]],
[["smtp 501"],["Syntax error in parameters or arguments"]],
[["smtp 502"],["Command not implemented"]],
[["smtp 503"],["Bad sequence of commands"]],
[["smtp 504"],["Command parameter not implemented"]],
[["smtp 550"],["Requested action not taken: mailbox unavailable"]],
[["smtp 551"],["User not local; please try <forward-path>"]],
[["smtp 552"],["Requested mail action aborted: exceeded storage allocation"]],
[["smtp 553"],["Requested action not taken: mailbox name not allowed"]],
[["smtp 554"],["Transaction failed"]]
]
