SMTP transaction error (SMTP error 451 4.7.1 Try again later)

gevelr

Hi all,
I'v got an issue with fetchmail. I get frequent SMTP error 451 4.7.1 Try again later.

logging:
Feb 11 12:31:45 mailserver systemd[1]: Started A remote-mail retrieval utility.
Feb 11 12:31:45 mailserver fetchmail[1899]: starting fetchmail 6.4.22 daemon
Feb 11 12:31:46 mailserver fetchmail[1899]: 2 messages for <redacted emailadress> at <redacted pop3 server> (157282 octets).
Feb 11 12:31:46 mailserver fetchmail[1899]: reading message <redacted emailadress>@<redacted pop3 server>:1 of 2 (98960 octets) (log message incomplete)
Feb 11 12:31:46 mailserver fetchmail[1899]: Connection errors for this poll:
name 0: connection to localhost:smtp [::1/25] failed: Connection refused.
name 1: connection to localhost:smtp [127.0.0.1/25] failed: Connection refused.
Feb 11 12:31:46 mailserver fetchmail[1899]: SMTP connect to localhost failed
Feb 11 12:31:46 mailserver fetchmail[1899]: SMTP transaction error while fetching from <redacted emailadress>@<redacted pop3 server> and delivering to SMTP host localhost
Feb 11 12:31:46 mailserver fetchmail[1899]: Query status=10 (SMTP)
Feb 11 12:41:47 mailserver fetchmail[1899]: 3 messages for <redacted emailadress> at <redacted pop3 server> (246696 octets).
Feb 11 12:41:49 mailserver fetchmail[1899]: reading message <redacted emailadress>@<redacted pop3 server>:1 of 3 (98960 octets) flushed
Feb 11 12:41:51 mailserver fetchmail[1899]: reading message <redacted emailadress>@<redacted pop3 server>:2 of 3 (58322 octets) flushed
Feb 11 12:41:52 mailserver fetchmail[1899]: reading message <redacted emailadress>@<redacted pop3 server> q:3 of 3 (89414 octets) (log message incomplete)
Feb 11 12:41:52 mailserver fetchmail[1899]: SMTP error: 451 4.7.1 Try again later
Feb 11 12:41:52 mailserver fetchmail[1899]: not flushed

Version info:
ANSI_COLOR="0;36"
BUG_REPORT_URL="https://github.com/grommunio"
CPE_NAME="cpe:/o:opensuse:leap:15.6"
DOCUMENTATION_URL="https://docs.grommunio.com/"
HOME_URL="https://grommunio.com/"
ID="grommunio-lds"
ID_LIKE="suse opensuse"
NAME="grommunio"
PRETTY_NAME="grommunio 2025.01.1"
PRIVACY_POLICY="https://grommunio.com/privacy/"
SUPPORT_URL="https://community.grommunio.com/"
VARIANT="grommunio appliance"
VARIANT_ID="appliance"
VERSION_ID="15.6"
VERSION="2025.1.1"

As far as I can see, Fetchmail tries to deliver a message to my local smtp host, but the connection sometimes gets refused by localhost:smtp [127.0.0.1/25]...
Any ideas on how to solve this issue?

Thanks,
Rutger

mwilliams

gevelr

Please check what your postfix tells you at that time: journalctl -fu postfix

eryx

I also had this issue. for me it was the greylisting rspamd was doing

WalterH

You may create two files and instruct grommunio-antispam do not check connections on localhost.
/etc/grommunio-antispam/local.d/multimap.conf:

IP_WHITELIST {
      type = "ip";
      prefilter = true;
      map = "${LOCAL_CONFDIR}/local.d/ip_whitelist.map";
      action = "accept";
  }

and /etc/grommunio-antispam/local.d/ip_whitelist.map:

# this may prevent DKIM signing?
127.0.0.1

Restart grommunio-antispam:
systemctl restart grommunio-antispam

Report back if this helps?

gevelr

Hi Walter,

Thanks for your response! I have created the two files and restarted antispam. The error is still occuring. Here is logging:

Feb 19 12:32:07 mailserver postfix/qmgr[1869]: 3FAA16A932C: from=<redacted_from>, size=25906, nrcpt=2 (queue active)
Feb 19 12:32:07 mailserver postfix/smtp[17610]: 3FAA16A932C: to=<redacted_to>, relay=::1[::1]:24, delay=0.57, delays=0.56/0.01/0/0, dsn=2.0.0, st>
Feb 19 12:32:07 mailserver postfix/smtpd[17601]: D8CD66A932D: client=localhost[::1]
Feb 19 12:32:07 mailserver postfix/cleanup[17604]: D8CD66A932D: message-id=6a223b89.AWwAAGO9IRAAAAAAAAAAAZSA2OUAAAAClbwAAAAAACjwDwBnq5d2@mailjet.com
Feb 19 12:32:08 mailserver postfix/cleanup[17604]: D8CD66A932D: milter-reject: END-OF-MESSAGE from localhost[::1]: 4.7.1 Try again later; from=<6a223b89.AW>
Feb 19 12:32:08 mailserver postfix/smtpd[17601]: 3C4636A932D: client=localhost[::1]
Feb 19 12:32:08 mailserver postfix/cleanup[17612]: 3C4636A932D: message-id=3806e4f3.AVMAAGHMrhUAAAAAAAAAAZSA2OUAAAAClbwAAAAAACjwDwBnrHGH@mailjet.com
Feb 19 12:32:08 mailserver postfix/smtp[17609]: 3FAA16A932C: to=archive@mailarchive.redacted, relay=192.168.16.10[192.168.16.10]:10025, delay=0.64,>
Feb 19 12:32:08 mailserver postfix/qmgr[1869]: 3FAA16A932C: removed
Feb 19 12:32:08 mailserver postfix/cleanup[17604]: 4A36D6A932E: message-id=20250219113208.4A36D6A932E@mailserver.redacted
Feb 19 12:32:08 mailserver postfix/cleanup[17612]: 3C4636A932D: milter-reject: END-OF-MESSAGE from localhost[::1]: 4.7.1 Try again later; from=<3806e4f3.AV>
Feb 19 12:32:08 mailserver postfix/smtpd[17601]: 92C8D6A932C: client=localhost[::1]
Feb 19 12:32:08 mailserver postfix/cleanup[17604]: 92C8D6A932C: message-id=9abe122e.AWoAAGNmrjIAAAAAAAAAAZSA2OUAAAAClbwAAAAAACjwDwBnrKi9@mailjet.com
Feb 19 12:32:08 mailserver postfix/cleanup[17604]: 92C8D6A932C: milter-reject: END-OF-MESSAGE from localhost[::1]: 4.7.1 Try again later; from=<9abe122e.AW>
Feb 19 12:32:09 mailserver postfix/smtpd[17601]: 237446A932C: client=localhost[::1]
Feb 19 12:32:09 mailserver postfix/cleanup[17612]: 237446A932C: message-id=67b5238571148_1f1ff82218c26e7@jobs0.soms.fi001.nl.freedomnet.nl.mail
Feb 19 12:32:09 mailserver postfix/qmgr[1869]: 237446A932C: from=<redacted_from>, size=26412, nrcpt=2 (queue active)
Feb 19 12:32:09 mailserver postfix/smtp[17609]: 237446A932C: to=<redacted_to>, relay=::1[::1]:24, delay=0.36, delays=0.35/0/0/0, dsn=2.0.0, statu>
Feb 19 12:32:09 mailserver postfix/smtpd[17601]: disconnect from localhost[::1] ehlo=1 mail=9 rcpt=9 data=6/9 rset=3 quit=1 commands=29/32
Feb 19 12:32:09 mailserver postfix/smtp[17610]: 237446A932C: to=archive@mailarchive.redacted, relay=192.168.16.10[192.168.16.10]:10025, delay=0.41,>
Feb 19 12:32:09 mailserver postfix/qmgr[1869]: 237446A932C: removed
Feb 19 12:32:09 mailserver postfix/cleanup[17604]: CB1EA6A932D: message-id=20250219113209.CB1EA6A932D@mailserver.redacted

Regards,
Rutger

WalterH

Try to edit the file:

/etc/grommunio-antispam/local.d/ip_whitelist.map:

# this may prevent DKIM signing?
127.0.0.1
[::1]

Add [::1] for IPv6 localhost and restart grommunio-antispam

gevelr

I am still getting the SMTP error 451 4.7.1 Try again later, after changing the ip_whitelist.map and adding [::1]...

However if I create/edit the file
/etc/grommunio-antispam/local.d/greylist.conf
to:
enabled = false;

Then the error disappears after restarting grommunio-antispam...

BTW, numerous sources indicate the rspamd greylist feature as the cause (for a long time)...

Regards,
Rutger

RathosTV

Big thanks to you WalterH, after including your changes it seem to work 🙏
The message: "SMTP-Fehler: 451 4.7.1 Try again later" disappeared 😅👍

RathosTV

rejoiced too soon, the message reappeared 😳
I now edit greylist.conf -> enabled = false, and I will check if this works,
thank you Rutger :-)

gevelr

I can confirm that the errors have disappeared after disabling greylist.
I have no idea what functionality I have disabled, but rspamd seems to function just fine...

Regards,
Rutger