Glossary
DMARC alignment
DMARC alignment is the requirement that the domain in a message's visible From address matches the domain that passed the SPF or DKIM check.
Why it matters when you send from your own Gmail
Passing SPF or DKIM is not enough on its own: a message can pass both and still fail DMARC if the passing domain is a different one. Alignment is relaxed when the two domains share the same organisational domain, and strict when they must be identical. This is where tools that send your email through their own servers go wrong. Honest Intros sends through your own Gmail account, so the message leaves Google's servers under your own address and the From domain is the one that signs.
Example
A message says From: you@yourcompany.com, but a third-party server signs it with its own domain. DKIM passes, yet the domains do not match, so the message is not aligned and DMARC fails.
What to do
When you test authentication, check that the passing domain is your own and not a tool's. If a service signs with its own domain, set it up to sign with yours, or stop sending through it.
Related terms
All terms are on the glossary.