Responses Sorted by Message

March 26, 2020 Contributors

SMTP Code Enhanced Code Message Comment
550 5.7.1 550 [internal] [oob] bounce_logger module
550 5.6.0 Body line too long (see RFC2822 section 3.5) See message.
503 5.5.1 DATA without MAIL FROM See message.
503 5.5.1 DATA without RCPT TO See message.
550 5.6.0 Header line too long (see RFC2822 section 3.5) See message.
550 5.6.0 Header not terminated by CR LF (see RFC2822 section 2.2) See message.
550 5.6.0 Invalid header found (see RFC2822 section 3.6) See message.
550 5.6.0 Lone CR or LF in body (see RFC2822 section 2.3) See message.
550 5.6.0 Lone CR or LF in headers (see RFC2822 section 2.2) See message.
501 5.5.1 MAIL FROM already established See message.
501 5.5.2 MAIL FROM syntax error See message.
501 5.5.2 MAIL FROM syntax error Triggered by an invalid address
550 5.6.0 Missing CR LF . CR LF See message.
550 5.6.0 Missing required RFC2822 Date field (see RFC2822 section 3.6) See message.
554 No Valid Domain See message.
501 5.5.2 RCPT TO syntax error See message.
501 5.5.2 RCPT TO syntax error Triggered by an invalid address
503 RCPT TO without MAIL FROM See message.
550 5.5.1 RFC2821 HELO/EHLO needed See message.
550 5.6.0 Required headers not found (see RFC2822 section 3.6) See message.
4.3.0 Resource limitations, please try later See message.
421 4.4.5 Service unavailable System outage
452 4.5.3 Service unavailable, batch limit reached See message.
421 4.4.5 Service unavailable, concurrency limit reached System outage
452 4.5.3 Service unavailable, recipients per connection limit reached See message.
452 4.5.3 Service unavailable, recipients per message limit reached See message.
501 5.5.4 Syntax error (no parameters allowed) See message.
421 This message is being 421’d Service is unavailable
554 5.7.0 [internal] Blackholed "Blackhole" option is set to "internal"
450 4.4.1 [internal] Connection Timed Out See message.
554 5.4.5 [internal] Delivery not attempted (message expired) See message.
554 5.4.4 [internal] Domain Lookup Failed See message.
451 4.4.2 [internal] MAIL FROM argument hook failed See message.
451 4.4.2 [internal] MAIL FROM arguments too long See message.
554 5.7.0 [internal] Message manually purged Purged messages from the system console
5.7.0 [internal] Message manually purged Used console command, "fail domain name"
550 5.4.4 [internal] NULL MX domain does not accept mail See message.
451 4.4.1 [internal] No valid hosts See message.
451 4.4.1 [internal] No valid hosts (unable to make any connections) See message.
551 5.4.6 [internal] Private/Loopback Address See message.
451 4.4.2 [internal] RCPT TO argument hook failed See message.
451 4.4.2 [internal] RCPT TO arguments too long See message.
4.7.5 [internal] SSL cert common name does not match host See message.
4.7.5 [internal] SSL cert must be signed by a valid CA See message.
4.7.5 [internal] SSL certificate subject does not match host See message.
451 4.7.6 [internal] STARTTLS required but not advertised See message.
451 4.7.5 [internal] TLS negotiation failed See message.
451 4.4.2 [internal] XCLIENT argument hook failed See message.
451 4.7.6 [internal] XCLIENT required but not advertised See message.
451 4.7.6 [internal] XCLUSTERMETADATA required but not advertised Cluster-related error
451 4.7.6 [internal] XCLUSTERMETADATA supported version not advertised Cluster-related error
451 4.4.2 [internal] connection closed by remote host See message.
550 5.7.1 [internal] discarded by policy See message.
554 5.4.7 [internal] exceeded max retries without delivery See message.
554 5.4.7 [internal] exceeded max time without delivery See message.
451 [internal] memory shortage while determining tls parameters See message.
550 5.3.0 [internal] message body missing See message.
451 4.4.2 [internal] no BODY response See message.
451 4.4.2 [internal] no DATA response See message.
451 4.4.2 [internal] no HELO/EHLO response See message.
451 4.4.2 [internal] no MAIL FROM response See message.
451 4.4.2 [internal] no METADATA reponse Cluster-related error
454 4.4.4 [internal] no MX or A for domain See message.
421 4.4.0 [internal] no MXs for this domain could be reached at this time See message.
451 4.4.2 [internal] no RCPT TO response See message.
451 4.4.2 [internal] no RSET response See message.
451 4.4.2 [internal] no XCLIENT response See message.
451 4.4.2 [internal] no banner See message.
451 4.7.5 [internal] no clustermetadata go-ahead Cluster-related error
451 4.7.5 [internal] no tls go-ahead See message.
550 5.7.1 [internal] processed as FBL message, and disposition is blackhole FBL module
5.7.0 [internal] rejected by policy See message.
4.7.5 [internal] remote node SSL certificate not signed by a valid CA See message.
451 4.4.2 [internal] send BODY failed See message.
451 4.4.2 [internal] send DATA failed See message.
451 4.4.2 [internal] send HELO/EHLO failed See message.
451 4.4.2 [internal] send MAIL FROM failed See message.
451 4.4.2 [internal] send RCPT TO failed See message.
451 4.4.2 [internal] send RSET failed See message.
451 4.7.5 [internal] send STARTTLS failed See message.
451 4.4.2 [internal] send XCLIENT failed See message.
451 4.7.5 [internal] send XCLUSTERMETADATA failed Cluster-related error
451 4.4.2 [internal] send key failed Cluster-related error
451 4.4.2 [internal] send metadata failed Cluster-related error
451 4.4.2 [internal] send metadatadicts failed Cluster-related error
421 4.3.4 allocated resources exceeded System outage
503 5.5.1 bad sequence of commands See message.
454 certificate expired SSL related
454 certificate not yet valid: possible clock skew SSL related
4.3.5 configuration error, please try later See message.
5.5.0 error while reading body See message.
501 5.5.2 invalid EHLO See message.
501 5.5.2 invalid HELO See message.
501 5.5.4 invalid arguments to RSET See message.
421 4.3.0 message is too large to process at this time See message.
4.3.5 message not yet parsed, can’t reparse See message.
4.3.5 message parse and assemble didn’t round-trip See message.
552 5.3.4 message size limit exceeded See message.
551 5.7.1 recipient blackholed See message.
550 5.7.1 relaying denied See message.
451 4.3.0 transaction failed See message.
501 5.5.4 unexpected argument to DATA See message.
501 5.5.4 unexpected command See message.
500 5.5.2 unrecognized command See message.