Even after implementing the List-Unsubscribe header, the 'unsubscribe from mailing list' link is not displaying

Question

We are progressing with the implementation of the List-Unsubscribe header to comply with Gmail Sender Guidelines. While conducting tests, we noticed that the 'unsubscribe from mailing list' link is not appearing in the Gmail client on the recipient's end.

Is there any potential reason that comes to mind for this issue?

Below, I am providing the header data (with some information redacted for privacy).

Delivered-To: ****@*******.***
Received: by 2002:a05:6520:4646:b0:283:91a:1adb with SMTP id el6csp795303lkb;
        Thu, 7 Dec 2023 01:47:51 -0800 (PST)
X-Google-Smtp-Source: AGHT+IGkrxRIriFcwqWDTLZPZDyX5RuCa+ot/NqD6tt21gj6L277nrfC2x3Zl7JRzTu1QcYm9j7i
X-Received: by 2002:a05:6a20:1444:b0:187:eea9:73c5 with SMTP id a4-20020a056a20144400b00187eea973c5mr2887137pzi.3.1701942471560;
        Thu, 07 Dec 2023 01:47:51 -0800 (PST)
ARC-Seal: i=1; a=rsa-sha256; t=1701942471; cv=none;
        d=google.com; s=arc-20160816;
        b=GS5MDCFcvdw0Nx38THlBQmTf/KBckJf9kIS2ZKCVZoYvIdheBNA4vrTcYERxOILXIF
         QCQohBLkTVeVO9y1em0tTS5d7CEduYlNWoR6ay+CLzQSxNbpKtxvU8ECapg3mkxaLjcQ
         tDDAALDfRiDJxlsnrNmiITEBuVwNNmOldWXeUlKNN6OYqvBKqGaJghZS3B+HeoJ1AzjH
         o9/db0wY7T/LtBekGHcfQvBu33oBZUWpLmaNbBnKupglvx0kEc9foRaBL98jISXNEKD9
         uK4qxg4e421JDiaY+/w7yDjcNND0x38nhA4R8miCY4ujAm0J7AEyQTdXWVbbHqCojXyS
         weqw==
ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816;
        h=content-transfer-encoding:date:errors-to:from:list-unsubscribe
         :list-unsubscribe-post:message-id:mime-version:subject:to;
        bh=f6DQBjo8rYX19JpB+nIPzKzcW1UlXBE5kq7UPzfAJfg=;
        fh=m4DbYAsBOnwc1IUh2REZnorY/4DwaOqFeBwm9y++uQU=;
        b=qOyTVHWiNRQsIFjOQ/3BZwzjmympKlkaKuz0repcIqpRi4HPqh6XPA7xfTob34gamI
         gbga9G4Cj+5QC350sOoJEIrCIENRvNPIgdi8jk58KuLBhmwGRUhi3IZkGkWSdac0gnfI
         fvk11SsUHhFmfJIDbr31m8Vgm4kwbmknrdVbbkQKX1hSpcGpIZpYa34RkAyoJznGQJS6
         CFxCQAT2KaJMcKQS3PPkSy+VPS9W4eJuDO4Bapdj+WcSwnZQ8aCWutAJ8dtDSZHteKIS
         mBor2qgK2Qf3zuxvke8VAbKzoqqqooqA9RbbENf+IBawn3avvHTI1YXUM3A5JxW0wg3L
         8+7Q==
ARC-Authentication-Results: i=1; mx.google.com;
       spf=pass (google.com: domain of *****-*********-****************@*******.*** designates xxx.xxx.xxx.xxx as permitted sender) smtp.mailfrom=*****-*********-****************@*******.***
Return-Path: <*****-*********-****************@*******.***>
Received: from xx-xxxx-xx-xx ([xxx.xxx.xxx.xxx])
        by mx.google.com with SMTP id i1-20020a654841000000b005b90af19430si880828pgs.595.2023.12.07.01.47.50
        for <****@*******.***>;
        Thu, 07 Dec 2023 01:47:51 -0800 (PST)
Received-SPF: pass (google.com: domain of *****-*********-****************@*******.*** designates xxx.xxx.xxx.xxx as permitted sender) client-ip=xxx.xxx.xxx.xxx;
Authentication-Results: mx.google.com;
       spf=pass (google.com: domain of *****-*********-****************@*******.*** designates xxx.xxx.xxx.xxx as permitted sender) smtp.mailfrom=*****-*********-****************@*******.***
Received: (qmail 20406 invoked from network); 7 Dec 2023 18:47:49 +0900
Received: from unknown (HELO staging-server) (xx.xxx.xxx.xxx)
  by 0 with SMTP; 7 Dec 2023 18:47:49 +0900
X-Sender: *****-*********-****************@*******.***
X-Mailer: Edge Mailer
To: ****@*******.***
Subject: title
Return-Path: *****-*********-****************@*******.***
Mime-Version: 1.0
Message-Id: <**********.20293.lKhhZA@staging-server>
List-Unsubscribe-Post: List-Unsubscribe=One-Click
List-Unsubscribe: <https://api.********.***/*****************>
From: ****@*******.***
Errors-To: *****-*********-****************@*******.***
Date: Thu, 7 Dec 2023 18:47:49 +0900
Content-Type: text/plain; charset="iso-2022-jp"
Content-Transfer-Encoding: 7bit

Demetri

Answer 1

Yes, we are seeing that too: https://github.com/knadh/listmonk/issues/1655 - per my tests in the first reply, the list-unsubscribe header doesn't seem to have any use currently -- it seems to be something gmail does automatically. I'm not seeing any info on list-unsubscribe being deprecated but it does seem to be.

According to https://9to5google.com/2014/08/06/gmail-adds-easy-to-find-unsubscribe-button-next-to-senders-address/ it only shows up for emails in Gmail’s Promotions, Social, and Forums inboxes.

Screenplay

Answer 2

Gmail states in their docs that there is no guarantee the UNSUB link will appear at the top of the message even if you have it properly within your header.

Their explanation is that it is reserved for good senders, those who follow best practices. Senders deemed not "good" will not have the link appear.

Musselman