Gmail says our mail is missing one-click unsubscribe
RFC 8058 requires two headers: List-Unsubscribe (mailto: or https:) and List-Unsubscribe-Post: List-Unsubscribe=One-Click. The https: link must accept POST without further confirmation. Required since February 2024 for Gmail and Yahoo bulk senders (5000+/day).
Try this first
- 1Check outbound headers in a sent message. Both lines must be present on marketing mail. Transactional doesn't need it but may include it.
- 2On an ESP (Mailchimp, Brevo, Postmark): enable 'one-click unsubscribe' in campaign settings. Most ESPs do this automatically.
- 3Self-hosted MTA: add the two headers to your template and ensure the URL processes POST without login or confirmation.
- 4Unsubscribe must work within 2 days (Gmail requirement). Updating a suppression list is sufficient.
- 5Test on Gmail web: open your test message, click Unsubscribe at top, confirm. No popup, one click.
When to bring us in
Sending marketing from an M365 mailbox instead of an ESP, you won't reliably meet RFC 8058. Migrate to an ESP.
See also
- Our emails land in spam for some recipientsAlmost always an SPF, DKIM, or DMARC setting that is wrong or missing, or a sender name that mimics a well-known brand.
- Someone reports receiving phishing emails "from us"Read: spoofing. Someone is abusing your sender name, not necessarily your actual mailbox.
- An email bounces (NDR): delivery failedThe NDR text usually states the exact reason. Reading it is step one.
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