My Discourse forum on Digital Ocean has stopped accepting incoming email

Posted October 25, 2021 160 views
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On around 29 September 2021, my Discourse forum log shows that no new incoming messages to the forum were being received. No messages were being bounced either - messages sent to the forum now simply never make it to the forum software - they disappear without any kind of response.

No settings changes have been made to the forum software, or in Digital Ocean control panel. The forum MX settings as shown in my Digital Ocean control Panel are still in place and correct.

Mailgun is the email provider for the forum, but again no settings there have been changed, and there are no errors logged by Mailgun.

MXlookup for the forum domain shows no errors, though there is one warning ‘DMARC Quarantine/Reject policy not enabled’ - but this is unchanged from when the forum was receiving emails normally.

Why is this suddenly happening? More importantly, how can I resume normal behaviour?

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1 answer

Hi @ArchPrime,

This is really weird. What I’ll suggest is trying to send an e-mail from an external provider to any mailbox you have access on - That way, you can check your mail logs to see if the message was received, or if it didn’t reach at all, you’ll receive a bounce-back give you an error which then can be followed to the real issue.

Those are the first steps, I’ll recommend trying.

  • Thanks for your reply @KFSys!

    A bit more digging and it turns out the issue was related to a Let’s Encrypt certification method that changed on that date for all users. A full rebuilding of my Discourse docker image to use the latest version that had been recoded to address this change seems to have solved that particular issue, though some Let’s Encrypt certificate issues remain, which generate SSL warnings in some browsers: ‘your connection is not private

    • Hi @ArchPrime,

      Hmm, that’s very odd.

      Having said that, you can check the console of the browser that are showing the said error to see if anything can be tracked. It’s weird that some browsers are showing the Let’s Encrypt and others are not.

      If you are using an incognito browser, does it still happen?

      • Hi thanks for your reply

        Turns out the issue was that the site certificate was for my https: domain without the www prefix.
        A helpful member of Discourse Meta community tipped me off on how to set up a redirect by adding a few lines to the app.yml configuration file, so now that same certificate works for my url with and without the www prefix.