What's Exim retry time when outgoing mail encounters a 421 "Service not available - too busy"

Gino Viroli

Well-Known Member
Oct 2, 2007
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Root Administrator
My WHM > Tweak Settings > Email delivery retry time is set to 15 m

When sending a mail out sometime the server gets a 421 "Service not available - too busy", hence Exim queues the message.

From my understanding Exim should retry after 15 min, instead in these two examples he retries after about 50 min (at 15:19 then at 16:09 / at 15:21 then at 16:09)

Why does it take so much before retrying?

[email protected] [~]# exigrep "[email protected]" /var/log/exim_mainlog

2020-03-13 15:19:31 1jCl9v-00087c-FP <= [email protected] H=(W764BIT) [151.41.210.200]:20021 P=esmtpsa X=TLSv1.2:ECDHE-RSA-AES256-SHA384:256 CV=no A=dovecot_login:[email protected] S=7164 [email protected] T="Re: Hello form Florida" for [email protected]
2020-03-13 15:19:31 1jCl9v-00087c-FP Sender identification U=mydom D=mydomain.com S=[email protected]
2020-03-13 15:19:31 1jCl9v-00087c-FP SMTP connection outbound 1584109171 1jCl9v-00087c-FP mydomain.com [email protected]
2020-03-13 15:19:32 1jCl9v-00087c-FP == [email protected] R=dkim_lookuphost T=dkim_remote_smtp defer (-44) H=smtp.aliceposta.it [82.57.200.133]: SMTP error from remote mail serverafter RCPT TO:<[email protected]>: 421 <[email protected]> Service not available - too busy
2020-03-13 16:09:21 1jCl9v-00087c-FP Sender identification U=mydom D=mydomain.com S=[email protected]
2020-03-13 16:09:24 1jCl9v-00087c-FP => [email protected] R=dkim_lookuphost T=dkim_remote_smtp H=smtp.aliceposta.it [82.57.200.133] C="250 <5E57C6B80487D695> Mail accepted"
2020-03-13 16:09:24 1jCl9v-00087c-FP Completed

2020-03-13 15:21:13 1jClBZ-0008AE-P8 <= [email protected] H=(W764BIT) [151.41.210.200]:20042 P=esmtpsa X=TLSv1.2:ECDHE-RSA-AES256-SHA384:256 CV=no A=dovecot_login:[email protected] S=7996 [email protected] T="Fw: Hello form Florida" for [email protected]
2020-03-13 15:21:13 1jClBZ-0008AE-P8 Sender identification U=mydom D=mydomain.com S=[email protected]
2020-03-13 15:21:13 1jClBZ-0008AE-P8 SMTP connection outbound 1584109273 1jClBZ-0008AE-P8 mydomain.com [email protected]
2020-03-13 15:21:14 1jClBZ-0008AE-P8 == [email protected] R=dkim_lookuphost T=dkim_remote_smtp defer (-44) H=smtp.aliceposta.it [82.57.200.133]: SMTP error from remote mail serverafter RCPT TO:<[email protected]>: 421 <[email protected]> Service not available - too busy
2020-03-13 16:09:24 1jClBZ-0008AE-P8 Sender identification U=mydom D=mydomain.com S=[email protected]
2020-03-13 16:09:25 1jClBZ-0008AE-P8 => [email protected] R=dkim_lookuphost T=dkim_remote_smtp H=smtp.aliceposta.it [82.57.200.133] C="250 <5E340AC20B970F77> Mail accepted"
2020-03-13 16:09:25 1jClBZ-0008AE-P8 Completed
 

cPanelLauren

Product Owner
Staff member
Nov 14, 2017
13,295
1,255
313
Houston
Hello,


The retry configuration is actually more complex than just every 15 minutes.

Code:
######################################################################
#                      RETRY CONFIGURATION                           #
######################################################################

# This single retry rule applies to all domains and all errors. It specifies
# retries every 15 minutes for 2 hours, then increasing retry intervals,
# starting at 1 hour and increasing each time by a factor of 1.5, up to 16
# hours, then retries every 8 hours until 4 days have passed since the first
# failed delivery.

# Domain               Error       Retries
# ------               -----       -------
The cPanel default for this is:
Code:
*                               *                               F,2h,15m; G,16h,1h,1.5; F,4d,8h
Based on that what's the output when looking directly at the transaction?

Code:
exigrep 1jCl9v-00087c-FP /var/log/exim_mainlog