Check whether a domain or its mail server’s IP is on spam blocklists — the usual reason email suddenly stops arriving.
For a domain we check the IPs of its mail and web servers.
We ask well-known free blocklists about each address.
Each listing links to that list’s removal page.
A blocklist listing is a common reason, but missing SPF, DKIM or DMARC and poor sending reputation matter too. Check email security as well.
Usually a hacked account, an unprotected contact form or a shared IP used by someone else. Fix the cause before asking for removal, or you’ll be listed again.
Not yet. Spamhaus, SURBL, URIBL and Barracuda need a commercial licence or registration to query, so a clean result here doesn’t cover them.