email.no_mx
The domain resolves but publishes no MX records at all.
What it looks at#
A DNS-over-HTTPS query for the domain’s MX records (Cloudflare’s resolver by default,
overridable for self-hosted deployments). If the query succeeds and the domain exists, but
returns zero MX records, this fires.
This checks whether mail can be routed to the domain — not whether the specific mailbox exists. It is not a mailbox-existence check; that would require actually connecting to the receiving mail server (a separate, narrower component this gate doesn’t include; see the gate overview).
Why it matters#
Without an MX record, nothing you send to this address will be accepted — the receiving side of email delivery simply isn’t configured. A confirmation email, a password reset, or a receipt sent here bounces immediately.
What to do#
High severity blocks by default, unless your product deliberately accepts addresses it knows are currently undeliverable (e.g. pre-registration before a domain’s mail is set up) — that’s a product decision, not something this check makes for you.