SMTP Status Codes and Error Messages from Error 451


SMTP status code – 451 – Requested action aborted – Local error in processing. or Requested action delayed – Local problem or <IP_Address> has recently sent spam
(also called SMTP Error 4.5.1)
SMTP Error 451 : The action has been aborted by the
ISP’s server. “Local” (Local Problem, Local Error) refers
to the next server that your message will go through after
leaving your server, typically your ISP’s server, or the
SMTP relaying service you are using, or, if your mail server
is sending directly to the destinations, the destination mail
server. This error is usually due to overloading at your
ISP or your SMTP relaying service from [temporarily]
too many messages or some other similar transient
failure. Typically some [hopefully] temporary event
prevents the successful sending of the message. The next
attempt to send by your server may prove successful.
If this error keeps occurring to the point that it has
effectively lost its transient nature and has become

….. frequent (!!), then the problem is at your end and
you should check your own mail server (if you email out of
a corporate network), communications on your side (router,
server network card), or inform your ISP if your mail server
relays through your ISP or if you are a home user emailing
out through Outlook, Outlook Express, Windows Mail, or
similar email program.
Examples of typical SMTP Error 451 return messages :
“SMTP error 451 Unable to complete command, DNS not
available or timed out” or “451 Domain of sender
address does not resolve” or “451 Error getting LDAP
results in map”, or “451 4.7.1 Greylisting in action,
please come back in 00:02:00 [minutes]” or “The
message that you sent has been delayed. The reason
given for the delay : 451 Temporary local problem – please
try later.”.

With the original SMTP standards having been invented
before spam became the scourge of the Internet, there are
no SMTP error codes dedicated to anti-spam errors. As a
result, SMTP Error 451 is now increasingly also used
to indicate that a message has been rejected by the
remote server because of anti-spam measures. A
typical error might be, for example : “SMTP error from
remote mail server after end of data, host
<host_address>: 451 <ip_address> has recently sent
spam. If you are not a spammer, please try later.”.
If all anti-spam related SMTP 451 errors are as descriptive
as the one above, then the error itself will tell you what you
need to do. As a general rule, however, you will most
times need to take some measures to have either your
server, or your ISP’s server, taken off some Internet
blacklist used by the recipient

Above are list of SMTP Errors Codes and Status Codes along with Error and Warning messages from Error 451 received while performing certain operation against mail server applications or related products.

What are SMTP Error Messages?
Simple Mail Transfer Protocol (SMTP) is an Internet standard for electronic mail (e-mail) transmission. SMTP protocol is used for sending e-mail messages between servers. Most e-mail systems that send mail over the Internet use SMTP to send messages from one server to another; the messages can then be retrieved with an e-mail client using either POP or IMAP.

In general, each SMTP error contains the following information:
• The SMTP Status Code or SMTP Error Codes or SMTP Reply Codes
• The message text. This text is usually returned with the Error code. Some messages employ word substitution, where the word substituted represents the system-replacement of a term more specific to the occurrence.
• An explanation of how the error may have occurred.

Hope this was helpful.

SQLServerF1 Team
Information about SMTP Error Codes or Status Codes and Error Messages on Windows, Linux Operating Systems.


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