Mail via a forwarder (Mailman, alumni list) fails DMARC
Forwarders break SPF and sometimes DKIM. ARC headers let receivers see the original auth, if the forwarder adds them.
Try this first
- 1Ask the forwarder if it supports ARC signing
- 2Enable ARC on the forwarder if the option exists
- 3Check Gmail's Authentication-Results header for 'arc=pass'
- 4No ARC support: replace the forwarder or upgrade the list software
When to bring us in
Many older listservers don't support ARC. Moving to Groups.io or Discourse fixes it.
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.
None of the above fits?
Describe your situation below. We pass your input plus the steps you already saw to our AI and return tailored next-step advice. If it's too risky to DIY, we'll say so.
Or skip the DIY entirely
Our Managed IT clients do not look these things up. One point of contact, a fixed monthly price, resolved within working hours.