SMTP Status Codes and Error Messages from Error 501
SMTP status code – 501 – Syntax error in parameters or arguments (e.g. invalid email address) Can sometimes also be indicative of communication problems
(also called SMTP Error 5.0.1)
SMTP Error 501 : The command was correct and
recognised, but the parameters (the arguments, e.g. email
address) were not valid.
For example, the following email address will definitely give
an SMTP Error 501 with most mail servers,
happy\firstname.lastname@example.org, as “\” is not allowed in email
addresses, which makes this email address invalid.
In the vast majority of cases SMTP Error 501 is caused
by invalid email addresses, an invalid domain name
recipient, or a Unix / Linux SEND MAIL command
which does not follow the established standards.
For example, a typical return error message might be :
“<remote-server-ip-address> does not like recipient.
Remote host said: 501 Invalid Address”.
In cases where the error is not caused by an invalid email
address, or by the failure to assign a valid email address to
the mandatory “From” property, an SMTP Error 501,
particularly if repeated, can be indicative of
communications problems, such as a noisy line,
intermittent drops in network connections, etc…
If you write your own SMTP program, rather than use
established SMTP software, you may get a 501 error if you
send to recipients hosted on a Microsoft Exchange server
and you add a trailing space or dot to the domain name in
your programming code. In such case you will typically get
a “501 5.5.4 Invalid Address” error. See this Microsoft
Knowledgebase article for more details :
Lastly, if you virus scan incoming emails on an Exchange
server, with the antivirus scanning software integrated into
Exchange, then the problem may be a bug in your antivirus
software – try turning it off to see if the problem
Above are list of SMTP Errors Codes and Status Codes along with Error and Warning messages from Error 501 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.
Information about SMTP Error Codes or Status Codes and Error Messages on Windows, Linux Operating Systems.