E-Mail (SMTP) error codes

The classic SMTP error code consists of three digits (e.g. 220 mail.domain.tld SMTP ready.). The ESMTP status codes are additions to the classic code and consist of digits devided by dots (5.1.1 User unknown.). Many times you see both types of code combined (e.g. 550 5.1.1 User unknown). Find below a list of the most common codes:

2xx Request ok. Go ahead.

220 Mail service is running (ESMTP ready).

221 2.0.0 Closing connection (Mail received successfully, Goodbye).

250 2.0.0 Message accepted for delivery

250 2.1.0 Sender e-mail address ok.

250 2.1.5 Recipient e-mail address ok.

3xx Request ok, but more input is needed to complete the action successfully.

354 Enter mail, end with CRLF.CRLF

4xx Temporary error, try again.

421 4.2.1 The service is not available and the connection will be closed.

441 4.4.1 Cannot connect to remote host (host has DNS entry, but can’t be connected to).

450 4.5.0 Mailbox temporarily unavailable.

451 4.1.8 Sender e-mail address domain does not resolve temporarily.

451 4.7.1 Greylisting in action, please come back later.

454 4.7.0 TLS not available due to local problem. Please try again later.

5xx Permanent error. Don’t try again.

500 5.5.1 Syntax error, command unrecognized.

503 5.5.0 Sender e-mail address already specified.

503 5.5.1 Need MAIL before RCPT.

544 5.4.4 Host not found (not in DNS).

550 5.1.1 Mailbox does not exist.

550 5.1.3 Bad e-mail address syntax.

550 5.7.0 Your IP address is in a blacklist.

553 5.1.8 Sender e-mail address domain does not exist.
553 5.1.8 Sender address rejected by address filter.

554 5.7.1 Relaying denied.

16 thoughts on “E-Mail (SMTP) error codes”

  1. I have an application which sends mail to the user who register them in the site. In UAT environment the mail is successfully sent. But in another environment same application is unable to send the mail. Telnet works from both environment to the SMTP server. please find the logs
    1.error env mail failed logs

    [9/22/14 18:13:50:097 GMT+05:30] 00000015 SystemOut O DEBUG SMTP: useEhlo true, useAuth false
    [9/22/14 18:13:50:097 GMT+05:30] 00000015 SystemOut O DEBUG SMTP: trying to connect to host “192.168.171.249”, port 25, isSSL false
    [9/22/14 18:13:50:173 GMT+05:30] 00000015 SystemOut O 220 MUMDCSMTP02 Microsoft ESMTP MAIL Service, Version: 7.0.6002.18264 ready at Mon, 22 Sep 2014 18:14:12 +053
    0
    [9/22/14 18:13:50:174 GMT+05:30] 00000015 SystemOut O DEBUG SMTP: connected to host “192.168.171.249”, port: 25

    [9/22/14 18:13:50:174 GMT+05:30] 00000015 SystemOut O EHLO chenachmis02t.npci.org.in
    [9/22/14 18:13:50:212 GMT+05:30] 00000015 SystemOut O 250-MUMDCSMTP02 Hello [192.168.179.248]
    250-TURN
    250-SIZE 2097152
    250-ETRN
    250-PIPELINING
    250-DSN
    250-ENHANCEDSTATUSCODES
    250-8bitmime
    250-BINARYMIME
    250-CHUNKING
    250-VRFY
    250 OK
    [9/22/14 18:13:50:212 GMT+05:30] 00000015 SystemOut O DEBUG SMTP: Found extension “TURN”, arg “”
    [9/22/14 18:13:50:212 GMT+05:30] 00000015 SystemOut O DEBUG SMTP: Found extension “SIZE”, arg “2097152”
    [9/22/14 18:13:50:212 GMT+05:30] 00000015 SystemOut O DEBUG SMTP: Found extension “ETRN”, arg “”
    [9/22/14 18:13:50:213 GMT+05:30] 00000015 SystemOut O DEBUG SMTP: Found extension “PIPELINING”, arg “”
    [9/22/14 18:13:50:213 GMT+05:30] 00000015 SystemOut O DEBUG SMTP: Found extension “DSN”, arg “”
    [9/22/14 18:13:50:213 GMT+05:30] 00000015 SystemOut O DEBUG SMTP: Found extension “ENHANCEDSTATUSCODES”, arg “”
    [9/22/14 18:13:50:213 GMT+05:30] 00000015 SystemOut O DEBUG SMTP: Found extension “8bitmime”, arg “”
    [9/22/14 18:13:50:213 GMT+05:30] 00000015 SystemOut O DEBUG SMTP: Found extension “BINARYMIME”, arg “”
    [9/22/14 18:13:50:213 GMT+05:30] 00000015 SystemOut O DEBUG SMTP: Found extension “CHUNKING”, arg “”
    [9/22/14 18:13:50:214 GMT+05:30] 00000015 SystemOut O DEBUG SMTP: Found extension “VRFY”, arg “”
    [9/22/14 18:13:50:214 GMT+05:30] 00000015 SystemOut O DEBUG SMTP: Found extension “OK”, arg “”
    [9/22/14 18:13:50:215 GMT+05:30] 00000015 SystemOut O DEBUG SMTP: use8bit false
    [9/22/14 18:13:50:216 GMT+05:30] 00000015 SystemOut O MAIL FROM:
    [9/22/14 18:13:50:251 GMT+05:30] 00000015 SystemOut O 250 2.1.0 achops@npci.org.in….Sender OK
    [9/22/14 18:13:50:251 GMT+05:30] 00000015 SystemOut O RCPT TO:
    [9/22/14 18:13:50:287 GMT+05:30] 00000015 SystemOut O 550 5.7.1 Unable to relay for mail4mrpradeep@gmail.com
    [9/22/14 18:13:50:288 GMT+05:30] 00000015 SystemOut O DEBUG SMTP: Invalid Addresses
    [9/22/14 18:13:50:288 GMT+05:30] 00000015 SystemOut O DEBUG SMTP: mail4mrpradeep@gmail.com
    [9/22/14 18:13:50:288 GMT+05:30] 00000015 SystemOut O DEBUG SMTP: Sending failed because of invalid destination addresses
    [9/22/14 18:13:50:288 GMT+05:30] 00000015 SystemOut O RSET
    [9/22/14 18:13:50:327 GMT+05:30] 00000015 SystemOut O 250 2.0.0 Resetting
    [9/22/14 18:13:50:327 GMT+05:30] 00000015 SystemOut O javax.mail.SendFailedException: Invalid Addresses;
    nested exception is:
    2.sucess mail sent log
    [9/22/14 20:05:16:916 IST] 00000036 SystemOut O DEBUG SMTP: useEhlo true, useAuth false
    [9/22/14 20:05:16:916 IST] 00000036 SystemOut O DEBUG SMTP: trying to connect to host “192.168.171.249”, port 25, isSSL false
    [9/22/14 20:05:16:987 IST] 00000036 SystemOut O 220 MUMDCSMTP02 Microsoft ESMTP MAIL Service, Version: 7.0.6002.18264 ready at Mon, 22 Sep 2014 20:07:43 +0530
    [9/22/14 20:05:16:987 IST] 00000036 SystemOut O DEBUG SMTP: connected to host “192.168.171.249”, port: 25

    [9/22/14 20:05:16:987 IST] 00000036 SystemOut O EHLO cheachuatapp01.npci.org.in
    [9/22/14 20:05:17:022 IST] 00000036 SystemOut O 250-MUMDCSMTP02 Hello [192.168.179.241]
    250-TURN
    250-SIZE 2097152
    250-ETRN
    250-PIPELINING
    250-DSN
    250-ENHANCEDSTATUSCODES
    250-8bitmime
    250-BINARYMIME
    250-CHUNKING
    250-VRFY
    250 OK
    [9/22/14 20:05:17:022 IST] 00000036 SystemOut O DEBUG SMTP: Found extension “TURN”, arg “”
    [9/22/14 20:05:17:022 IST] 00000036 SystemOut O DEBUG SMTP: Found extension “SIZE”, arg “2097152”
    [9/22/14 20:05:17:022 IST] 00000036 SystemOut O DEBUG SMTP: Found extension “ETRN”, arg “”
    [9/22/14 20:05:17:022 IST] 00000036 SystemOut O DEBUG SMTP: Found extension “PIPELINING”, arg “”
    [9/22/14 20:05:17:022 IST] 00000036 SystemOut O DEBUG SMTP: Found extension “DSN”, arg “”
    [9/22/14 20:05:17:022 IST] 00000036 SystemOut O DEBUG SMTP: Found extension “ENHANCEDSTATUSCODES”, arg “”
    [9/22/14 20:05:17:022 IST] 00000036 SystemOut O DEBUG SMTP: Found extension “8bitmime”, arg “”
    [9/22/14 20:05:17:022 IST] 00000036 SystemOut O DEBUG SMTP: Found extension “BINARYMIME”, arg “”
    [9/22/14 20:05:17:022 IST] 00000036 SystemOut O DEBUG SMTP: Found extension “CHUNKING”, arg “”
    [9/22/14 20:05:17:022 IST] 00000036 SystemOut O DEBUG SMTP: Found extension “VRFY”, arg “”
    [9/22/14 20:05:17:022 IST] 00000036 SystemOut O DEBUG SMTP: Found extension “OK”, arg “”
    [9/22/14 20:05:17:022 IST] 00000036 SystemOut O DEBUG SMTP: use8bit false
    [9/22/14 20:05:17:023 IST] 00000036 SystemOut O MAIL FROM:
    [9/22/14 20:05:17:058 IST] 00000036 SystemOut O 250 2.1.0 achops@npci.org.in….Sender OK
    [9/22/14 20:05:17:058 IST] 00000036 SystemOut O RCPT TO:
    [9/22/14 20:05:17:092 IST] 00000036 SystemOut O 250 2.1.5 testmail@gmail.com
    [9/22/14 20:05:17:093 IST] 00000036 SystemOut O DEBUG SMTP: Verified Addresses
    [9/22/14 20:05:17:093 IST] 00000036 SystemOut O DEBUG SMTP: testmail@gmail.com
    [9/22/14 20:05:17:093 IST] 00000036 SystemOut O DATA
    [9/22/14 20:05:17:128 IST] 00000036 SystemOut O 354 Start mail input; end with .
    [9/22/14 20:05:17:128 IST] 00000036 SystemOut O From: achops@npci.org.in

  2. just trying to send mail with several photos & i get… smtp error [221] 2.0.0 bye
    what does this mean & how do i sort it? thanks

    1. [221] 2.0.0 bye is not an error. It is just confirming that you are ending the connection with the other mail server. Is that happening for all recipients?

  3. An internal CRM application that sends email now throws this message:

    Date : 3/24/2014 2:47:41 PM
    Description : Unable to connect to SMTP server.

    03/24/14 14:47:40 Opening Socket.
    Performing DNS lookup: smtpout.secureserver.net
    Connecting to: 68.178.252.101
    connection error: 0

  4. HI,
    Couls you please provide solution to error mentioned below :-
    The following recipient(s) cannot be reached:

    ‘Catherine Valenza’ on 2/26/2014 1:44 PM
    554 5.1.8 – Invalid email domain for:
    cvalenza at truenorthhealthcenter.org [R0109008]

    Sending address is a roadrunner email address.

  5. Having this same problem this morning and the Domain IS valid. We had it checked. For some reason when I send from my home email, it comes back with the 554 5.1.8 code.

  6. Could you please provide solution to overcome “5.1.8 Sender e-mail address domain does not exist.”

    Thanks in advance.

    1. This means that the domain of the sender address does not exist. There is no way to overcome this. You have to send from a valid domain (e.g. hotmail.com, gmail.com etc.).

  7. Please could you provide solution to “Server error: ‘451 4.7.1 Greylisting in action, please come back later”.

    Thanks and kind regards.

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