Problem with mail server at - demanding Message-ID header

Is there a better place to report issues with mail server operated by Petites Singularités?

I received mail message from and I replied to it using my Tutanota mail.

My mail was not delivered because “Message-ID header in the email has been modified” according to response from

According to my research

  • Message-ID header header field was present in original message
  • Message-ID header field was missing in response
  • original Message-ID header was not preserved in any form in response
  • Message-ID header field is optional
  • Message-ID header is supposed to be unique per message, not message thread according to Message-ID wikipedia article (new user, unable to link it) so preserving it would be incorrect anyway

What is my mail client supposed to do to be able to deliver the mail message? I am asking as I plan to make a bug report/feature request to Tutanota developers but I am unsure what exactly my mail client is supposed to do.

Hi, thank you for reporting this.

Your message was successfully delivered to my email but indeed not to our Discourse instance.

ngi0-mentor is an alias that enables testing this kind of usage where a group can handle incoming email with Discourse. It is also delivering to a direct email address to avoid losing messages. I am not sure yet how to handle this since it could be anywhere from Tutanova to Discourse, but I suspect I sent you the original message from a mail client outside Discourse, and it detected your response as a reply to something it did not know. I think the best is to report to the Discourse team and see what they think. I will do that ASAP, but there’s no urgency on your side: if your using regular SMTP, I’m pretty sure the problem comes from Discourse.

We can check together and try to reproduce in the next few days. My take is that:

  1. I send you an email from a regular client
  2. You reply to it
  3. Discourse fails to recognize the original Message-ID since it does not have it.

If that fails according to specs, then we know what we’re dealing with. Otherwise we need to investigate your mail setup. 90% it’s on my side though. Don’t sweat it!

Thanks again for the report

And I got message back in my mail :slight_smile:

This account is a throwaway setup on a throwaway mail, so please send me mail to my Tutanota account if further info is needed.

1 Like

I also replied to “testing” mail.

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