Mails refusés par le destinataire

Bonjour,

Depuis plusieurs mois, je rencontre un problème pour les mails que j'envoie vers le domaine ardoc.be (hosté par one.com). Tous mes mails sont refusés immédiatement avec la réponse suivante (détail de la réponse):

Received: by mo552.mail-out.ovh.net (Postfix)
id 4XqcFL5YGXz1Zmj; Fri, 15 Nov 2024 12:45:42 +0000 (UTC)
Received: from in44.mail.ovh.net (unknown [10.101.4.44])
by vr29.mail.ovh.net (Postfix) with ESMTP id 4XqcFM05RLz4XpqPB
for ; Fri, 15 Nov 2024 12:45:43 +0000 (UTC)
Received: from 8.mo552.mail-out.ovh.net (8.mo552.mail-out.ovh.net [46.105.37.156])
by in44.mail.ovh.net (Postfix) with ESMTPS id 4XqcFL6Rl6z2xsXCs
for ; Fri, 15 Nov 2024 12:45:42 +0000 (UTC)
Received: from DAG3EX2.mxp3.local (172.16.2.6) by DAG7EX1.mxp3.local
(172.16.2.13) with Microsoft SMTP Server (version=TLS1_2,
cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.39; Fri, 15 Nov
2024 13:45:43 +0100
Received: from DAG7EX1.mxp3.local (172.16.2.13) by DAG7EX3.mxp3.local
(172.16.2.75) with Microsoft SMTP Server (version=TLS1_2,
cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.39 via Mailbox
Transport; Fri, 15 Nov 2024 13:45:43 +0100
Received: from vr29.mail.ovh.net (unknown [10.101.8.29])
by out44.mail.ovh.net (Postfix) with ESMTP id 4XqcFM1PrQzbH0cb6
for ; Fri, 15 Nov 2024 12:45:43 +0000 (UTC)
Received: from output44.mail.ovh.net (164.132.34.44) by mxplan3.mail.ovh.net
(172.16.2.6) with Microsoft SMTP Server (version=TLS1_2,
cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.39 via Frontend
Transport; Fri, 15 Nov 2024 13:45:43 +0100
From: "Mail Delivery System"
To:
Subject: Undelivered Mail Returned to Sender
Date: Fri, 15 Nov 2024 13:45:42 +0100
Message-ID: <4XqcFL5YGXz1Zmj@mo552.mail-out.ovh.net>
MIME-Version: 1.0
Content-Type: multipart/mixed;
boundary="----=_NextPart_000_002E_01DB3764.C3296990"
X-Mailer: Microsoft Outlook 16.0
Authentication-Results: in44.mail.ovh.net; dkim=none; dkim-atps=neutral
X-Ovh-Tracer-Id: 4789015256065213728
X-VR-SPAMSTATE: BOUNCE
X-VR-SPAMSCORE: 10000
X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgeefuddrvdeggdegudcutefuodetggdotefrodftvfcurfhrohhfihhlvgemucfqggfjpdevjffgvefmvefgnecuuegrihhlohhuthemucehtddtnecupfhothhifhhitggrthhiohhnucdluddttddttddmnecujfgurhepfffhuffvgggtsehptddtredttddvnecuhfhrohhmpefotefknffgtfdqffetgffoqffpsehmohehhedvrdhmrghilhdqohhuthdrohhvhhdrnhgvthculdforghilhcuffgvlhhivhgvrhihucfuhihsthgvmhdmnecuggftrfgrthhtvghrnhepkeekuddvleduheehkeehtdefueffgfeliedufeefveevgfeivefhvedtueegudfgnecuffhomhgrihhnpehovhhhrdhnvghtrdhimhdpohhnvgdrtghomhenucfkphepgeeirddutdehrdefjedrudehieenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepihhnvghtpeegiedruddthedrfeejrdduheeipdhhvghlohepkedrmhhoheehvddrmhgrihhlqdhouhhtrdhovhhhrdhnvghtpdhnsggprhgtphhtthhopedupdhrtghpthhtohepohhlihhvihgvrhestghhrghtthhlrghinhdrsggvpdfovfetjfhoshhtpehvrhdvlegmpdgukhhimhepnhhonhgvmgdpshhpfhepnhhonhgvmgdprhgvvhfkrfepkedrmhhoheehvddrmhgrihhlqdhouhhtrdhovhhhrdhnvghtmgdpghgvohfkrfephfft
X-Ovh-Spam-Status: OK
X-Ovh-Spam-Reason: vr: BOUNCE; dkim: disabled; spf: disabled
X-Ovh-Message-Type: BOUNCE
X-OVH-Remote: 46.105.37.156 (8.mo552.mail-out.ovh.net)
X-MS-Exchange-Organization-Network-Message-Id: 8cc100ea-0851-4ac0-25c8-08dd05736b1e
X-MS-Exchange-Organization-PRD: mo552.mail-out.ovh.net
X-MS-Exchange-Organization-SenderIdResult: None
X-MS-Exchange-Organization-AVStamp-Enterprise: 1.0
X-MS-Exchange-ABP-GUID: 00aa00e7-5bbe-489a-b5c5-55148bb67f00
X-MS-Exchange-Organization-AuthSource: DAG3EX2.mxp3.local
X-MS-Exchange-Organization-AuthAs: Anonymous
X-MS-Exchange-Transport-EndToEndLatency: 00:00:00.2929369
X-MS-Exchange-Processed-By-BccFoldering: 15.01.2507.039
Thread-Index: AQLvu1giZQeFhP8BtIO0Ltbu6aRZ5w==
X-OlkEid: 000000009CFAC0AA5CDC5A4D98F2A03318F13EE60700C3B68E10F77511CEB4CD00AA00BBB6E600000000000C0000128EE950A6A19942B5CEE24A63B93FE80000000006090000E47235BEB5B9354B8928316DADB52790


Une ligne en particulier attire mon attention :
X-Ovh-Spam-Reason: vr: BOUNCE; dkim: disabled; spf: disabled

En effet, le SPF est bel et bien configuré dans mon DNS:
chattlain.be.
chattlain.be.
0 SPF v=spf1 include:mx.ovh.com ~all

Merci pour vos retours...