The user JustinSjouw is troubleshooting incoming email issues in a self-hosted Discourse setup using the mail-receiver container. Despite correct DNS settings (verified via MXToolbox) and manual polling enabled, emails are not being received. The issue is traced to a firewall blocking SMTP traffic on port 25, which is required for the mail-receiver to receive emails. After opening the necessary port, the problem is resolved. JammyDodger and IAmGav assist by confirming the setup and suggesting troubleshooting steps, including checking DNS and firewall settings. Justinvolved confirms the resolution and suggests adding a note about firewall ports to the official guide for future users JammyDodger agrees and updates the guide accordingly.
I have setup a Discourse environment per the standard Docker container and added the mail-receiver container.
When I look at https://mxtoolbox.com/ my domain community.mountainbikemuseum.net also points to the right IP address of my server.
On the mail-receiver container no information seems to be logged, the last line of ./launcher logs mail-receiver
looks like this:
Feb 09 08:54:24 ubuntu-mail-receiver postfix/master[1]: daemon started – version 3.5.6, configuration /etc/postfix
And "./launcher logs mail-receiver | grep receive-mail " does not show any information.
When I send an e-mail to an address @community.mountainbikemuseum.net nothing shows in the admin panel under the “rejected” section.
What could I look at next?
As you’ve got the Feb 09 08:54:24 ubuntu-mail-receiver postfix/master[1]: daemon started – version 3.5.6, configuration /etc/postfix log, but you don’t get a rejected email, it makes me think the problem could be in the DNS section of the guide.
Regarding your 3 steps:
1 there is no mailbox so I cannot login to it, the mail should be directly picked up by the service in the additional container right?
2 is set manual polling (instead of pop3)
3 not sure i quite understand this step
Apart from checking over your DNS MX records manually (and double checking the guide), I’m not sure. I’ve only set the mail-receiver up a handful of times, and it’s been pretty plain-sailing every time (not to rub it in). When I check the mx:community.mountainbikemuseum.net mx record it says its not the fully qualified domain name, so I can’t tell if the mx records are pointing to the right place. (Edit: I put a www. in front It’s inconclusive, but looks similar to my working one. I’ve sent a test email to it just on the offchance)
@IAmGav may be on to something that I can’t spot, so hopefully he can give you a bit more detail about those steps.
Just to confirm, you’re the OP with another account?
I’ll throw in a link to the Troubleshooting section for good measure.
Having a little search, it seems to suggest the mail-receiver uses port 25, and that some providers can block this. It’s also possible you have something else interfering. I’m afraid I don’t have much experience of this though. Is there anything unusual about your set-up?
I think in the troubleshooting section at point 2 Did the e-mail even make it to mail-receiver ?
It would be nice to add a line to check if there is a firewall that blocks incoming smtp traffic, ideally maybe even link to something describing the exact ports that should be open. (I have a firewall config panel that automatically adds 25, 587 and 465, but would be nice to know what the mail-receiver is actually listening on)
It’s inconclusive, but looks similar to my working one. I’ve sent a test email to it just on the offchance)
I can’t access that topic - do you mind sharing what the problem/resolution was?
Thanks for the help!