Knowledgebase

SMTP Reply Codes

See rfc1893 and rfc2034 for information about enhanced status codes.

Check the RFC index for further mail-related RFCs.

Reply codes in numerical order
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

Reply codes grouped by command
Command	Code	Description
connect
	220	<domain> Service ready
	421	<domain> Service not available, closing transmission channel
HELO
	250	Requested mail action okay, completed
	500	Syntax error, command unrecognised
	501	Syntax error in parameters or arguments
	504	Command parameter not implemented
	521	<domain> does not accept mail [rfc1846]
	421	<domain> Service not available, closing transmission channel
EHLO
	250	Requested mail action okay, completed
	550	Not implemented
	500	Syntax error, command unrecognised
	501	Syntax error in parameters or arguments
	504	Command parameter not implemented
	421	<domain> Service not available, closing transmission channel
MAIL
	250	Requested mail action okay, completed
	552	Requested mail action aborted: exceeded storage allocation
	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
	421	<domain> Service not available, closing transmission channel
RCPT
	250	Requested mail action okay, completed
	251	User not local; will forward to <forward-path>
	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
	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
	503	Bad sequence of commands
	521	<domain> does not accept mail [rfc1846]
	421	<domain> Service not available, closing transmission channel
DATA
	354	Start mail input; end with <CRLF>.<CRLF>
	451	Requested action aborted: local error in processing
	554	Transaction failed
	500	Syntax error, command unrecognised
	501	Syntax error in parameters or arguments
	503	Bad sequence of commands
	421	<domain> Service not available, closing transmission channel
received data
	250	Requested mail action okay, completed
	552	Requested mail action aborted: exceeded storage allocation
	554	Transaction failed
	451	Requested action aborted: local error in processing
	452	Requested action not taken: insufficient system storage
RSET
	200	(nonstandard success response, see rfc876)
	250	Requested mail action okay, completed
	500	Syntax error, command unrecognised
	501	Syntax error in parameters or arguments
	504	Command parameter not implemented
	421	<domain> Service not available, closing transmission channel
SEND
	250	Requested mail action okay, completed
	552	Requested mail action aborted: exceeded storage allocation
	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
	421	<domain> Service not available, closing transmission channel
SOML
	250	Requested mail action okay, completed
	552	Requested mail action aborted: exceeded storage allocation
	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
	421	<domain> Service not available, closing transmission channel
SAML
	250	Requested mail action okay, completed
	552	Requested mail action aborted: exceeded storage allocation
	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
	421	<domain> Service not available, closing transmission channel
VRFY
	250	Requested mail action okay, completed
	251	User not local; will forward to <forward-path>
	550	Requested action not taken: mailbox unavailable
	551	User not local; please try <forward-path>
	553	Requested action not taken: mailbox name not allowed
	500	Syntax error, command unrecognised
	501	Syntax error in parameters or arguments
	502	Command not implemented
	504	Command parameter not implemented
	421	<domain> Service not available, closing transmission channel
EXPN
	250	Requested mail action okay, completed
	550	Requested action not taken: mailbox unavailable
	500	Syntax error, command unrecognised
	501	Syntax error in parameters or arguments
	502	Command not implemented
	504	Command parameter not implemented
	421	<domain> Service not available, closing transmission channel
HELP
	211	System status, or system help reply
	214	Help message
	500	Syntax error, command unrecognised
	501	Syntax error in parameters or arguments
	502	Command not implemented
	504	Command parameter not implemented
	421	<domain> Service not available, closing transmission channel
NOOP
	200	(nonstandard success response, see rfc876)
	250	Requested mail action okay, completed
	500	Syntax error, command unrecognised
	421	<domain> Service not available, closing transmission channel
QUIT
	221	<domain> Service closing transmission channel
	500	Syntax error, command unrecognised
TURN
	250	Requested mail action okay, completed
	502	Command not implemented
	500	Syntax error, command unrecognised
	503	Bad sequence of commands

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