DKIM problem 2022

My YunoHost server

Hardware: VPS bought online
YunoHost version:
I have access to my server : Through SSH | through the webadmin
Are you in a special context or did you perform some particular tweaking on your YunoHost instance ? : no

Description of my issue

Dunno exactly since how long it stopped working but it dont work any more.
It was ok when I’ve done the initial mail setup.
I checked /etc/dkim files and entry on DNS are these are ok, not changed.
All services on the yuno server as displayed as “OK”.
As indicated in another post, I sent a message to and the result is :

SPF check: pass
“iprev” check: pass
DKIM check: none

So the problem should be on the yuno server side and probably some update did not worked as expected but I did not see anything since I dont use the mail server usually.
Somehow the yuno server dont or cant use the DKIM files or DKIM is no more used by the server.

In addition I cant send any message using rainloop but cant find any log. Just get “can’t send message”. This is where I first see there was a problem. I’ve sent the message to port25 using command line.

You forgot to actually describe the problem … What doesn’t work anymore exactly … and how do you know it’s not working

It seemed clear to me.
The problem is that the mail server dont use DKIM any more as shown in the response to the test : DKIM check: none instead of normal DKIM check: pass. Just like if DKIM was not configured at all.

Is this the only way you noticed this ?

How exactly did you send the email to ? Note that when using the mail command from CLI, no DKIM info is added, it’s added only when the client properly authenticates against the SMTP server

I use :
echo “something” | mailx -s “subject”
I thought DKIM signature was added by mail server whatever mail client was used. I there a way to use DKIM with CLI ?

Not that I know of, you have to use a proper mail client such as Roundcube, Rainloop, Snappy, Thunderbird, K9mail, … or a CLI-based mail client which actually connects on SMTP, but mail(x) from the command line doesn’t do this.

Rainloop and roundcube are not able to send the mails. Error message is displayed by roundcube : “SMTP Error (451) : Failed to add recipient” and rainloop just display “cant send message”.
But, anyway, mailx actually send the mail using the smtp server. Otherwise how could I get a response from port25 ?

By connect, I meant “authenticate”, i.e. with a proper login/password. When using mailx you ain’t entering a login/password, so I don’t know how it effectively sends the email, maybe root just magically adds the mail into the mail queue, i don’t know. Sounds like there’s some mechanism for unix users to send mails without going through the usual SMTP submission process.

Anyway, I’m not the one who invented this, I actually spent countless hours trying to debug DKIM before understanding this

Yeah so again it comes back to “what is your actual problem” in this story. One doesn’t randomly end up testing DKIM from the command line. What are you trying to achieve in terms of “things that regular humans want to do in their regular life” …

Ok, so, I try to send mail using the postfix mail server on my yuno box using rainloop (and then roundcube).
As it’s not working I try to investigate and search in logs.
As I find nothing in logs I try to send mail directly using mailx and it works but without DKIM signature. And be sure mailx is properly using postfix. root is authorized to send mails.
Just sent a mail using mailx to my work mail here is an extract of the message (just changed, server IP, server name and destination mail address) :

Received: from (LHLO ( by with LMTP; Wed, 5 Oct 2022 09:09:38 +0200
Received: from localhost (localhost [])
by (Postfix) with ESMTP id 0AB7AC556C
for; Wed, 5 Oct 2022 09:09:38 +0200 (CEST)
Received: from ([])
by localhost ( []) (amavisd-new, port 10024)
with ESMTP id nFmhvGQuJ4-C for;
Wed, 5 Oct 2022 09:09:37 +0200 (CEST)
Received: from ( [])
by (Postfix) with ESMTPS id 4D0DCC5A55
for; Wed, 5 Oct 2022 09:09:26 +0200 (CEST)
Received: from ( [])
(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
(No client certificate requested)
by (asm) with ESMTPS id 35FD960128
for; Wed, 5 Oct 2022 09:09:17 +0200 (CEST)
Subject: subject
Date: Wed, 5 Oct 2022 07:09:25 +0000 (UTC)
From: root
X-Renater-SpamState: 0
X-Renater-SpamScore: 0
X-Renater-SpamCause: gggruggvucftvghtrhhoucdtuddrgedvfedrfeeivddgudduiecutefuodetggdotefrodftvfcurfhrohhfihhlvgemucftgffptefvgfftpdggtfgfnhhsuhgsshgtrhhisggvnecuuegrihhlohhuthemuceftddtnecunecujfgurhepuffvkfffhfestddtfedttddttdenucfhrhhomheprhhoohhtuceorhhoohhtsehphhhighgrmhhmrgdrfhhrqeenucggtffrrghtthgvrhhnpefghffhveduhfegkeehhfdvtedvheettdethfdukefggfduffevudetieektefgkeenucfkphepudelfedrjedtrddvrddvjeenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmhhouggvpehsmhhtphdphhgvlhhopehphhhighgrmhhmrgdrfhhrpdhinhgvthepudelfedrjedtrddvrddvjedpmhgrihhlfhhrohhmpehrohhothesphhhihhgrghmmhgrrdhfrhdpnhgspghrtghpthhtohepuddprhgtphhtthhopehjrggtqhhuvghsrdhgrghrnhhivghrsehinhhsrgdqlhihohhnrdhfrh
X-Bizanga: IMP -


Ok, so you can stop thinking mailx not really sending mails.
So from bottom to top, first I try to use some cli mail senders in order to be sure postfix/dovecot are configured ok and then if it works in cli, I’ll try to see if mail clients are working back.
I continue to investigate trying to force mailx to sign with DKIM but did not found something clear so far.

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