Mail with List-Unsubscribe-Post header does not get whitelisted in DKIM headers

[julianlam]

Issue Summary

I am attempting to integrate one-click unsubscribe to my emails. I have List-Id and List-Unsubscribe headers set up, and recently added List-Unsubscribe-Post, following RFC8058. Unfortunately, Gmail will not show the "Unsubscribe" button.

#4 of the spec specifies:

4. Additional Requirements

The message needs at least one valid authentication identifier. In
this version of the specification, the only supported identifier type
is DKIM [RFC6376]. Hence, senders MUST apply at least one valid DKIM
signature to the message.

The List-Unsubscribe and List-Unsubscribe-Post headers MUST be
covered by the signature and included in the "h=" tag of a valid
DKIM-Signature header field.

If the message does not have the required DKIM signature, the mail
receiver SHOULD NOT offer a one-click unsubscribe for that message.

(Emphasis mine)

Here are the headers as reported by Gmail:

List-Id: <digest.2.my.site>
List-Unsubscribe: <https://my.site/email/unsubscribe/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ0ZW1wbGF0ZSI6ImRpZ2VzdCIsInVpZCI6MiwiaWF0IjoxNTUwNzAwMTY3LCJleHAiOjE1NTMyOTIxNjd9.gExTDZ4qbbSqClIazz2Cc38tXQY2E-A-LzcvrsFG1rs>
List-Unsubscribe-Post: List-Unsubscribe=One-Click

However, here is the DKIM signature, note the missing List-Unsubscribe-Post header, although list-unsubscribe is present.

DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nodebb.org; h=content-transfer-encoding:content-type:from:mime-version:list-id: list-unsubscribe:subject:to; s=s1; bh=ecVCRuV9D20XWPvAhAezXrbVGtbF+HhsiPKNYErwQHw=;

I have an authenticated domain with SendGrid, and use Automated Security. I believe the missing header in the DKIM-Signature field may be the reason why Gmail refuses to show the Unsubscribe button.

Technical details:

• sendgrid-nodejs Version: v6.3.1
• Node.js Version: v10.15.1

[thinkingserious]

Hello @julianlam,

Thanks for submitting a GitHub issue! We are very sorry that you are running into this problem. In order to better serve you, as this does not present itself as a library specific issue, we would like to ask that you reach out to our support team at https://support.sendgrid.com.

Thank you!

SendGrid DX Team

[fannigurt]

Any news about this issue? I'm Python SDK user, experienced the same issue - List-Unsubscribe-Post header does not get whitelisted in DKIM headers.
How could I add it via API?
Dkim-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sendgrid.info; h=content-transfer-encoding:content-type:from:mime-version:subject: reply-to:list-unsubscribe:x-feedback-id:to;

sendgrid==6.1.0
python 3.7

[julianlam]

@fannigurt Despite the suggestion from @thinkingserious, the SendGrid team seemingly does not consider this high priority. I have opened a support ticket, and they've essentially passed the buck over to Gmail, and suggested I send mailto: instead of http: in list-unsubscribe.

So basically, there's not much support for list-unsubscribe-post...?

The ticket: https://support.sendgrid.com/hc/en-us/requests/1941763?flash_digest=73772eec7f0a813f891b294090fb70bea78b85f9

[fannigurt]

@julianlam we can make the full message by ourselves and sign it with custom DKIM, but wait, why we need Sendgrid? 😁
Ok, seems like we need to build a new bike: make mailto: format and then using Imbound Parse hook the unsubscribe message from user client, parse it and make unsubscription in database. Looks strange 🤔

[VolneiMonteiroRibeiro]

@julianlam you try?
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nodebb.org; h=content-transfer-encoding:content-type:from:mime-version:list-id: list-unsubscribe:list-unsubscribe-post:subject:to; s=s1; bh=ecVCRuV9D20XWPvAhAezXrbVGtbF+HhsiPKNYErwQHw=;