- go to settings>privacy&security and untick junk settings

As mentioned in my post, I've already followed all the suggestions that I've found, including unticking junk settings as you say. It doesn't work. See attached screenshots of global and account settings.

I can only offer a suggestion: check online to see if your email provider is marking messages as junk. Otherwise, I'm clueless.

Regardless of what the email provider may be adding to the headers, I don't want Thunderbird to do anything; just leave all arriving messages in the Inbox. I picked one of the "junked" messages and posted the headers into my mail service provider's checker, and it said there was nothing wrong with it; so I don't think the service provider is doing this.

I did see this header: X-GND-Status: PHISHING which I guess may be something that Thunderbird reacts to. But, I reiterate, I don't want this behaviour; I want to turn it off.

Please post a screen shot of the message list of the spam folder, with the spam column visible

@Wayne Mery: Screenshot attached

@david: The only info from my service provider (gandi.net) is that they might do this on SPF or DKIM failures. But there doesn't seem to be any evidence of that in the headers of the NoIP message shown in the screenshot.

The only suspicious thing in the headers, as far as I can see, is the "X-GND-Status: PHISHING" that I mentioned before. Headers (I hope they paste OK): Return-Path: <bounces+1423439-bed8-jeff=jamcupboard.co.uk@em3906.noip.com> Delivered-To: jeff@jamcupboard.co.uk Received: from o5.em01.www.noipmarketing.com (o5.em01.www.noipmarketing.com [167.89.33.4]) by spool.mail.gandi.net (Postfix) with ESMTPS id E70599418D5 for <jeff@jamcupboard.co.uk>; Sun, 25 Aug 2024 16:05:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=noip.com; h=subject:from:mime-version:to:content-type:cc:content-type:from: subject:to; s=s1; bh=jBTit+tjFRa5r4xTRXMExgX9PVVCZBCdEpdCAsfcpyA=; b=LBbrYC0jZ4sn0W4vwsx8loOIZbp24D40cgqqgFTm3dgaPreYVY/ITGPK0/ecu3tGJED5 OgIZXGkZc+YMzl//URvpNOwJMtdqPIElM1GbN/4NXxtFv8sE0yx5BIrt2MnkBPRj0Jh/Cm Gec1N+HqqmalvGyVQQHpyQ/lnL05DWP+Z7IGprre7QlW8AAmvj0hiNfDdDUO/G4Tc94OoT un7z2GzYvr3ffhWAG3zXpeXZBItmi0kVB1v9GLXKFrNcll5APOG2X4uNeE13zZ+3QQy9KE 8qeDbeNts1gyjIZSLOpY7cW2qjl2yy1xQd0CtewW/m9Tx0cHV/82/w7wCxIesMbQ== Received: by recvd-68b757b7d7-4kd4c with SMTP id recvd-68b757b7d7-4kd4c-1-66CB563C-A 2024-08-25 16:05:16.68806447 +0000 UTC m=+323027.169739311 Received: from www.noip.com (unknown) by geopod-ismtpd-5 (SG) with ESMTP id SZsfGMjITBe8b3LxHWqP1A for <jeff@jamcupboard.co.uk>; Sun, 25 Aug 2024 16:05:16.599 +0000 (UTC) Message-ID: <e8d1bb6c44d6ad86d4014097a2d073ca@swift.generated> Date: Sun, 25 Aug 2024 16:05:16 +0000 (UTC) Subject: ACTION REQUIRED: jamcupboard.hopto.org is Expiring Soon From: No-IP Notices <notice-26094761@noip.com> MIME-Version: 1.0 X-SG-EID:

=?us-ascii?Q?u001=2Eoi4RWJM3NUA3Ssq=2FOdLhs3EtuUXvzVevbGjYJrtMDz3eEfVgysXmQGULz?=
=?us-ascii?Q?z9XxGMaU9pgFcu5OTPrgrSrZz=2FUkw9lcSgG96DU?=
=?us-ascii?Q?lnqe6smdlm2nvxGNOYzB7mlMc1sAgqvMUGreTZH?=
=?us-ascii?Q?kKgisOBeqI4dTdujJ+b3oEUxJokZZZ6lSJ4KIeH?=
=?us-ascii?Q?B1rhw+utRISLRAmotaR2quhpz+NytUSFcJw7N2A?=
=?us-ascii?Q?I5HTRRk5YBu1rzcxek+RauXoYf5KGN+75eYeOJu?= =?us-ascii?Q?DPom?=

X-SG-ID:

=?us-ascii?Q?u001=2ESdBcvi+Evd=2FbQef8eZF3BtGh8lUg0V9kjW2ZWGo2tDKosLvHFqdDzGUir?=
=?us-ascii?Q?nMDdAhtyQakhijCLzc8EFrzdEqQv8HBTVL12ga=2F?=
=?us-ascii?Q?SlTWzSQA8PmG8zzJIiQEnaNPVcToo3+Ovc0TC1+?=
=?us-ascii?Q?ZR1HtO=2FJ=2FHjx=2FAg=3D=3D?=

To: Jeff Silver <jeff@jamcupboard.co.uk> X-Entity-ID: u001.hvlCMewRlm7HYqxBaVwI8w== Content-Type: multipart/alternative;

boundary="_=_swift_1724601916_9f5dd43ab5b7b68ea01c4a5e00687c85_=_"

X-GND-Status: PHISHING Authentication-Results: spool.mail.gandi.net; dkim=pass header.d=noip.com header.s=s1 header.b=LBbrYC0j; dmarc=pass (policy=none) header.from=noip.com; spf=pass (spool.mail.gandi.net: domain of bounces@em3906.noip.com designates 167.89.33.4 as permitted sender) smtp.mailfrom=bounces@em3906.noip.com

I have found that my service provider (charter.net) automatically categorizes certain messages as Spam, and when that has happened they seem to be downloaded automatically into the Junk folder.

If gandi.net offers a web interface to their mail, you might check your Spam folder there, and see if they're doing something similar.

If so, I think you'll find that it is not Thunderbird Junk processing, but simply your provider saying "this message will be in the Junk folder when it is downloaded".