How to set up List-Unsubscribe on Microsoft 365

Step by step List-Unsubscribe setup for Microsoft 365: complete instructions, examples, verification commands, and common pitfalls.

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This is a reference guide for configuring List-Unsubscribe on Microsoft 365. Use it while editing DNS or when troubleshooting deliverability.

Tip: Avoid common mistakes: follow these steps to add List-Unsubscribe on Microsoft 365. Then verify everything with the InboxGreen Free Checker.

Provider-specific notes for Microsoft 365

  • Microsoft 365 DKIM requires enabling signing per domain in the Security center. The DNS CNAME records can exist but DKIM still fails until signing is turned on.
  • SPF is simple, but tenants using multiple mail flows often forget to add their marketing or transactional tool's include alongside the Microsoft include.
  • Microsoft 365 admin → Settings → Domains → Pick domain → View DNS records.

What is List-Unsubscribe?

List-Unsubscribe is a message header that gives inboxes a safe, machine readable way to unsubscribe. Gmail and Outlook often show a clear unsubscribe link when it is present and valid, which reduces spam complaints and protects your sender reputation.

How to enable it in practice

  1. In your sending platform, enable the List-Unsubscribe header or macro in templates.
  2. Use a one click HTTPS link as the main method, with a mailto address as fallback.
  3. Test by sending to a Gmail address and checking “Show original”.

Example headers

List-Unsubscribe: <https://yourdomain.com/u/abcd1234>, <mailto:[email protected]?subject=unsubscribe>
List-Unsubscribe-Post: List-Unsubscribe=One-Click

Common mistakes

  • Using a broken or redirected unsubscribe link that fails when clicked.
  • Only providing a mailto address without a one click URL.
  • Failing to apply the unsubscribe globally across lists and tools.

Related for Microsoft 365

quick_reference_all Set up SPF on Microsoft 365 quick_reference_all Set up DKIM on Microsoft 365 quick_reference_all Set up DMARC on Microsoft 365
Pro tip: Turn on InboxGreen Monitoring to check these records daily and get alerts if something breaks.

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