Respnding to private posts with in-reply-to header set

I see from search that in-reply-to is respected, but do I need to do anything special to enable it? I’ve got an email that was sent with these headers:

To: RemObjects <>
In-Reply-To: <topic/1000/>

(where 1000/80000 are valid numbers, but I replaced them with different values here), this post ended up creating a new post while it should have added to the existing 1000 topic. So do I need to do anything special to enable respecting in-reply-to?

Sorry, I don’t understand what you wrote? Email replies are working fine, in no case should an “accidental” new topic be created.

Sorry I should have been more clear. what I’m seeing is a user replying to an existing private post via email (post has the topic id 18192) with these headers:

18192 is a private post to which this user got an answer, he replied to the from address (instead of the reply-to address annoyingly). It created a new private post nr 18217.

X-Cyrus-Session-Id: sloti2d2t06-4012272-1544779320-2-6613197902708601977
X-Sieve: CMU Sieve 3.0
X-Spam-known-sender: no
X-Spam-score: 0.0
X-Spam-hits: HTML_MESSAGE 0.001, ME_BETA_RULES 0.01, RCVD_IN_DNSWL_NONE -0.0001,
X-Spam-charsets: plain='utf-8', html='utf-8'
From: <username>
To: RemObjects <>
Subject: AW:  [RemObjects Talk] [RemObjects Support] Water
Thread-Topic: [RemObjects Talk] [RemObjects Support] Water
Thread-Index: AdSRPsrWDFnNHZG0StuEFTwuVEVT7gA9h5uAACOlvLAAEz8aAAAfVnrQ
Date: Fri, 14 Dec 2018 09:21:55 +0000
Message-ID: <a36ce08cb72c4bcc855be2863d8ba3cb@REMOVED>
References: <8630089458304afd8c97fc5b328cd0b6@REMOVED>
In-Reply-To: <topic/18192/>
Accept-Language: de-DE, en-US
Content-Language: de-DE

my understanding was, that discourse takes in account the In-Reply-To field too, to match up the post to the original thread (in addition to the reply-to field used as To).

What I expected to happen is that it added it to the original topic, not a new one. Whats the best approach for me to diagnose this if that is what should have happened?

We use reply keys for matching, tiny guess, is this a very old topic user is replying to months later ?


nope the original thread is 6 days old, and this one is from friday.

Do you have an easy repro?


Do you have rules set up that direct emails to to a certain category?

Since the user emailed that address directly, that’s probably how it got handled.


Yes! Sales is setup to also accept mail for talk@ else that would get lost when the in reply is not set.

What would be the best way to catch ‘lost’ mails otherwise?

( is our discourse ‘from’ address)