[wp-trac] [WordPress Trac] #64368: `Could not instantiate mail function` errors sending mail in 6.9
WordPress Trac
noreply at wordpress.org
Sat Dec 13 00:44:15 UTC 2025
#64368: `Could not instantiate mail function` errors sending mail in 6.9
--------------------------+-----------------------
Reporter: desrosj | Owner: SirLouen
Type: defect (bug) | Status: accepted
Priority: normal | Milestone: 6.9.1
Component: Mail | Version: 6.9
Severity: normal | Resolution:
Keywords: has-patch | Focuses:
--------------------------+-----------------------
Comment (by SirLouen):
Just because I'm freaking devoted to this cause, I've purchased a cPanel
$2 hosting for one month @ this random hosting I've found
ethernetservers.com and I have associated one random domain I own.
It's remarkable how cPanel has evolved, it doesn't have that clunky
interface anymore :)
It even has this menu:
[[Image(https://i.imgur.com/VEinJEW.png)]]
That says which DNS you are missing and how to configure them.
Basically I configured the SPF, DKIM and DMARC with the values they
provided me in my domains DNS and installed the default WordPress with
that Softaculous thingy that is like very strightforward
After that I got into the WordPress admin, installed my trustworthy
`Health Check & Troubleshooting` plugin, and went straight to its tools to
test an email.
I have not added a single hook, the patching plugin that @westonruter
recommends, or anything. Just a clean, 6.9 WP installation and the Health
Check plugin to enable the simplest mail sending feature.
Here is the result (I have not redacted anything on purpose, so you can
clearly see the whole thing):
{{{
Delivered-To: sir.louen at gmail.com
Received: by 2002:a05:7011:21c8:b0:4f3:5ee4:767e with SMTP id
sh8csp536952mdb;
Fri, 12 Dec 2025 16:23:39 -0800 (PST)
X-Google-Smtp-Source:
AGHT+IEIG4AByFl/c5X3jy/ETyF955HTVaXbD12abH8uG8JZpgocwJy3FA9N4QSdpzeZM2Z7Lb8C
X-Received: by 2002:a05:6a00:1d9f:b0:7e8:450c:61a1 with SMTP id
d2e1a72fcca58-7f6696a3f77mr3496250b3a.56.1765585419060;
Fri, 12 Dec 2025 16:23:39 -0800 (PST)
ARC-Seal: i=2; a=rsa-sha256; t=1765585419; cv=pass;
d=google.com; s=arc-20240605;
b=XaTsgwbi/XOF9KxwkkOT17NuHtm+HazMyhDNCM8b4k2u2cUPkcOgJ26lVg5RIs7gM9
FTwffuzKqopLwUykWgUmtI72phDxIpHrfXE9OvnWV9MY6bEVOIUvbQyX+OQB7gEi7iSU
SvT/XUZOMDU3XQ+J6pXJGZsHB8v1RkRVmHdVVxbK+TaHFXAFF1xNYasstuuURxIw3uzF
zX3zckCeFLUIZ39DbBLB5qEigLp+UeChcM1JK+L+SkCJIvsUApGBXHq4lrHA8bX3tIB8
uNOPz9jgAdYaHMgxAwTcJojM3PRM+XbW9h4EKNMq0fUo2KbstC2tQOKV11TsrxX7DbWE
tyag==
ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=google.com;
s=arc-20240605;
h=content-transfer-encoding:mime-version:message-
id:from:date:subject
:to:dkim-signature;
bh=Wm2HU/yEKd8YMPMFnCMbH7gi0dnWYAjzo7s25HE4z84=;
fh=LnWiZB+0qsThBew1oCwmWb63UJ40SUAv5hSa6DrXbks=;
b=MUWVVUjMxeO4ysw6qogLsix1k3JOhijBPQkGbHCPReNpPxSJc3KUO3jfDZ0bHThiSs
JLhI2TthrEDHVaRb0kTP9hMGzWt+kaMfn9huIX/V4SXbSsS745O5vEItEOCBOHKbwPXS
ip8QPHJUKbnYm6A6Z+P9xBmTVaOrU18X29gtOPHN4HVfRbojyaQ4ns1r66IPkwXxbbkv
fNf6XG2WXog1L1IkfHy7/4LlaG5cKmybEg1I/5Mh6hohyA5pmLAMymxJPWNC5qzO6Rn8
L0T2EXc7QyUdS1XSu0aRArYcYS2Bitmsj9szuS7AMi7NtSueDN2pjvqwRC2bm38/gF/h
Qbfg==;
dara=google.com
ARC-Authentication-Results: i=2; mx.google.com;
dkim=pass header.i=@f1onboard.com header.s=default
header.b=j0wQ9LNh;
arc=pass (i=1);
spf=softfail (google.com: domain of transitioning
wordpress at f1onboard.com does not designate 23.83.209.81 as permitted
sender) smtp.mailfrom=wordpress at f1onboard.com
Return-Path: <wordpress at f1onboard.com>
Received: from hedgehog.birch.relay.mailchannels.net
(hedgehog.birch.relay.mailchannels.net. [23.83.209.81])
by mx.google.com with ESMTPS id
d2e1a72fcca58-7f4c5b4c704si11702101b3a.219.2025.12.12.16.23.38
for <sir.louen at gmail.com>
(version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256);
Fri, 12 Dec 2025 16:23:38 -0800 (PST)
Received-SPF: softfail (google.com: domain of transitioning
wordpress at f1onboard.com does not designate 23.83.209.81 as permitted
sender) client-ip=23.83.209.81;
Authentication-Results: mx.google.com;
dkim=pass header.i=@f1onboard.com header.s=default
header.b=j0wQ9LNh;
arc=pass (i=1);
spf=softfail (google.com: domain of transitioning
wordpress at f1onboard.com does not designate 23.83.209.81 as permitted
sender) smtp.mailfrom=wordpress at f1onboard.com
X-Sender-Id:
ethernetserversltd|x-authuser|fonboard at jazz.cleannameservers.com
Received: from relay.mailchannels.net (localhost [127.0.0.1]) by
relay.mailchannels.net (Postfix) with ESMTP id 6A240780790 for
<sir.louen at gmail.com>; Sat, 13 Dec 2025 00:23:38 +0000 (UTC)
Received: from jazz.cleannameservers.com (trex-
green-1.trex.outbound.svc.cluster.local [100.103.178.42]) (Authenticated
sender: ethernetserversltd) by relay.mailchannels.net (Postfix) with
ESMTPA id BAA74780F6D for <sir.louen at gmail.com>; Sat, 13 Dec 2025 00:23:37
+0000 (UTC)
ARC-Seal: i=1; a=rsa-sha256; d=mailchannels.net; s=arc-2022; cv=none;
t=1765585418;
b=6KoO4XlMEhP0kzSRdfL21cPAka/xQ74yGnaZPnmHk7ia8rAvzzVYnCh7MTtrelolAgNLq5
F5FDpY9ZMXSez0J2ges5/4+HCQJSu8ZS21ecA6SzVUkxRryIAjFPhkYHLNIR5xHi4V5TCR
vgVTuBgSE4mOc1duKR2ohrH+xUCGXd3OG8mBwqSz9Xd7X3XQA7HiepHc1s0COK5le0+MWx
P2RJxX4k84rSbWN8eUetS+izrEq456AHBR8BE4g6pFpffZLJoTE3OfbkVZkrIJVZS4dh9t
iQgGLZszX3vOc1rPyByBJdY7XEbVC0Vjrbe1MdbAoB6wgFKYVwaGmVBUMr4RbQ==
ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed;
d=mailchannels.net; s=arc-2022; t=1765585418; h=from:from:reply-
to:subject:subject:date:date:message-id:message-id:
to:to:cc:mime-version:mime-version:content-type:content-type:
content-transfer-encoding:content-transfer-encoding:dkim-
signature; bh=Wm2HU/yEKd8YMPMFnCMbH7gi0dnWYAjzo7s25HE4z84=;
b=L9WPNiZeKI/ROKSML5A00Ba0uXsC+zNbsTh6BwozYMA8OrrODun+9dC54ZM3avGFItKbbI
XllTpFPQOkS1hjCA6tVJq4UEzBa5p0W7izEggfmDLJzX4f8KPbYxZ0umzpLL83k68e/48T
IRW2yLq/ZJtIvEMKoIhuXqa9UHJIW0g1gx1WeBQTeSEtYMlBIQrlJ+H2knCdw0BuVdohRH
oBELFpPciK1oknwD8F6QNb5ZzFAzLEzytCAbc86o2ZXULkROXS3PVepvpPgGvPcd5JSEwV
g8a/tLfJUTmiGsu8sojekHIevSfDNlrrzNTfNDCIkIwhmG4o6rYKoLnYb6wriQ==
ARC-Authentication-Results: i=1; rspamd-6ccd5b4cc5-ggwd2; auth=pass
smtp.auth=ethernetserversltd smtp.mailfrom=wordpress at f1onboard.com
X-Sender-Id:
ethernetserversltd|x-authuser|fonboard at jazz.cleannameservers.com
X-MC-Relay: Neutral
X-MailChannels-SenderId:
ethernetserversltd|x-authuser|fonboard at jazz.cleannameservers.com
X-MailChannels-Auth-Id: ethernetserversltd
X-Absorbed-Reaction: 5db032cc14f1fe4c_1765585418272_1774664454
X-MC-Loop-Signature: 1765585418272:3610297220
X-MC-Ingress-Time: 1765585418272
Received: from jazz.cleannameservers.com (jazz.cleannameservers.com
[57.128.96.9]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384) by
100.103.178.42 (trex/7.1.3); Sat, 13 Dec 2025 00:23:38 +0000
DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed;
d=f1onboard.com; s=default; h=Content-Transfer-Encoding:Content-Type:
MIME-Version:Message-ID:From:Date:Subject:To:Sender:Reply-To:Cc:Content-
ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To
:Resent-Cc :Resent-Message-ID:In-Reply-To:References:List-Id:List-Help
:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive;
bh=Wm2HU/yEKd8YMPMFnCMbH7gi0dnWYAjzo7s25HE4z84=;
b=j0wQ9LNhNUPdDm8Od7EXPTooRA
SrRR4rpVbv6LXLos1eaLOzrhTWhd45syJbCR6+nPHZphuQ6LZR8aaKhme0zKDB6B8ZkMWulxJk+GR
FiCKwyBZYMpFUdZz9tky//rNkVOGNX92TvCiOexc+5BQbaycKkRaJSG/29d6b6e6q/pJ8qGnVa9w3
cE42kRnBXqemnn12Vd0lcqMbuQfi7s14DGNDsGmFuv90M8UVaA+KYQ/+wvssjBJS49AIQ5gp88K7i
zJTraVIWhwdR6Cfc/2QOtg3zKlTtZVqg+HTQqWa4HSX83b4BwaDl4BAAXqB8ck54R6pJA6G+szTRx
ZtmkYxew==;
Received: from fonboard by jazz.cleannameservers.com with local (Exim
4.98.2) (envelope-from <wordpress at f1onboard.com>) id 1vUDQ7-000000009Yv-
0ruG for sir.louen at gmail.com; Sat, 13 Dec 2025 00:23:35 +0000
To: sir.louen at gmail.com
Subject: Health Check – Test Message from https://f1onboard.com
Date: Sat, 13 Dec 2025 00:23:35 +0000
From: WordPress <wordpress at f1onboard.com>
Message-ID: <lUke7Mm5v1etKFKpMmGKGg0mvNblMEenzX37sdiLCfs at f1onboard.com>
X-Mailer: PHPMailer 7.0.0 (https://github.com/PHPMailer/PHPMailer)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
X-AuthUser: fonboard at jazz.cleannameservers.com
Hi! This test message was sent by the Health Check plugin from My Blog
(https://f1onboard.com) on December 13, 2025 at 12:23 am. Since you’re
reading this, it obviously works.
Additional message from admin: this is a test
}}}
Maybe the most important part:
{{{
Received: from fonboard by jazz.cleannameservers.com with local (Exim
4.98.2) (envelope-from <wordpress at f1onboard.com>) id 1vUDQ7-000000009Yv-
0ruG for sir.louen at gmail.com; Sat, 13 Dec 2025 00:23:35 +0000
}}}
Yes, the `envelope-from` is `wordpress at f1onboard.com` which I have not
created the inbox. I have not created any email inbox at all for that
domain. I have not even added the MX records, just in case you want to
inspect the DNS zone, I've just added the DMARC, the DKIM and the SPF as
the "Email Deliverability" menu suggests.
Conclusion: It's pretty straightforward. This is the defaults for 99.99%
of web hosts, as I've chosen the most cheapest and random host I've found
out there for the test. I understand that some hosts forcefully configured
the `-f` because we were missing it and this brought some problems. But
this has been fixed, so I'm confident at this point that we are good to
move on at this point.
--
Ticket URL: <https://core.trac.wordpress.org/ticket/64368#comment:53>
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