The author details a troubleshooting journey with email forwarding between Outlook and Gmail, where forwarded messages get rejected due to authentication failures. Despite passing SPF, DKIM, and DMARC checks on the original delivery, the re-sending via Outlook's forwarding mechanism causes Gmail to reject the message due to low domain reputation.
Background
Email authentication (SPF/DKIM/DMARC) is critical for deliverability, but forwarding can break these checks since the forwarding server becomes a new sending agent. This is a common pain point for users who rely on email forwarding across different providers.
- Source
- Lobsters
- Published
- Aug 22, 2026 at 05:53 PM
- Score
- 6.0 / 10