Outbound email issues for one domain

Hi all I have two CPanel servers (well, 2 I am interested in today): #1. Hosting server - at a host that blocks port 25 mail outbound. #2. Hosting server - with a host that allows port 25 mail outbound Server #1 uses -> Server #2 as a "smarthost" #whmapi1 installed_versions packages=1|grep exim #cpanel-exim: 4.94.2-4.cp1198 - cpanel-exim Both servers consistent with exim (as above) and cpanel 98.0.8 versions. Differences? #1 is CentOS8.4 while #2 is CentOS7.8 - CloudLinux Mail seems to flow for most / many of my hosted clients (sample testing shows no other unreasonable errors), so almost all good. One specific domain sender gives me errors sending to an external client self-hosted server (SBS2011 - Exchange), but seems to send ok otherwise. The specific messages bounce with failure message "all hosts for 'externalserver.sbs2011.domain' have been failing for a long time (and retry time not reached)" or "retry timeout exceeded" and initial defer messages "Connection timed out H=my.server#2 [ip.address]: SMTP timeout after initial connection" BUT.... if I send to that same external server from another account on Server#2, the email at externalserver.sbs2011.domain is processed / received ok. Likewise if I manually utilise telnet to create an email at externalserver.sbs2011.domain it works fine. I have been staring at this and testing as time permits for over week. Its time to ask the audience for clues :) Thanks in advance. Tony

cPRex Jurassic Moderator

September 22, 2021 16:08

Hey there! It sounds like there is a cached failure for that domain in Exim. Can you try running these commands to clear the retry database to see if that gets things working?

/usr/sbin/exim_tidydb -t 0d /var/spool/exim retry > /dev/null
/usr/sbin/exim_tidydb -t 0d /var/spool/exim reject > /dev/null
/usr/sbin/exim_tidydb -t 0d /var/spool/exim wait-remote_smtp > /dev/null

thowden

September 22, 2021 21:54

Hi cPRex I ran the three commands, without the dev/null just to see what was processed. The first one cleared a heap of 'too old' entries. The last one completed with: # /usr/sbin/exim_tidydb -t 0d /var/spool/exim wait-remote_smtp Tidying Exim hints database /var/spool/exim/db/wait-remote_smtp Tidying complete The middle one seems to want something different for its syntax: # /usr/sbin/exim_tidydb -t 0d /var/spool/exim reject Usage: exim_tidydb [-t ] = retry | misc | wait- | callout | ratelimit | tls I'll go an test if that made any difference. Thanks Tony

September 22, 2021 22:03

Hi No apparent difference after running those commands on both servers. Tony

September 23, 2021 13:11

I'm not really sure what could be causing that then - it would be best to have our team take a look directly at the server so we can see what's going on with that. If you're able to submit a ticket to our team, please post the number here so I can follow along and make sure this thread stays updated.

Outbound email issues for one domain

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