SMTP reply codes

See rfc2821 for the basic specification of SMTP; see also rfc1123 for important additional information. See rfc1893 and rfc2034 for information about enhanced status codes.Check the RFC index for further mail-related RFCs.

Code Meaning
200 (nonstandard success response, see rfc876)
211 System status, or system help reply
214 Help message
220 <domain> Service ready
221 <domain> Service closing transmission channel
250 Requested mail action okay, completed
251 User not local; will forward to <forward-path>
354 Start mail input; end with <CRLF>.<CRLF>
421 <domain> Service not available, closing transmission channel
450 Requested mail action not taken: mailbox unavailable
451 Requested action aborted: local error in processing
452 Requested action not taken: insufficient system storage
500 Syntax error, command unrecognised
501 Syntax error in parameters or arguments
502 Command not implemented
503 Bad sequence of commands
504 Command parameter not implemented
521 <domain> does not accept mail (see rfc1846)
530 Access denied (???a Sendmailism)
550 Requested action not taken: mailbox unavailable
551 User not local; please try <forward-path>
552 Requested mail action aborted: exceeded storage allocation
553 Requested action not taken: mailbox name not allowed
554 Transaction failed

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