My domain is listed on a blocklist — what does it mean and what do I do?

If WarmySender shows that your sending domain is listed on SURBL or Spamhaus, here is the calm version first: a listing is a flag that an independent list keeps on your domain name. It doesn’t stop your mail by itself, it doesn’t automatically mean you did anything wrong, and only that list can remove it. This page explains what you’re seeing, whether warmup had anything to do with it, and exactly how to ask for removal.

The short answer

• These lists track domain names, not the servers your mail is sent through.
• A listing doesn’t stop your mail by itself. Some spam filters use these lists; many don’t.
• A listing doesn’t automatically mean you did something wrong — a brand-new domain can be listed too.
• Only the list itself can remove a listing. WarmySender can’t request removal for you.
• Before you ask, pause warmup and campaigns on that domain yourself and keep warmup off until the list decides. WarmySender doesn’t pause them for you.

What you’re seeing

WarmySender checks every connected sending domain against two domain blocklists: the Spamhaus DBL (Spamhaus’s list of domains) and SURBL. A listing shows up in three places:

• Analytics → Deliverability → Domain Health. Your domain’s row shows a red Listed badge with a line underneath such as “Listed on SURBL, checked 2 hours ago”. The same table is on Analytics → Mailboxes & Domains.
• Dashboard → Smart Insights. A card names the listed domain.
• Warmup page. Each mailbox on that domain shows a “Domain on SURBL · see what to do” badge that links here.

Domain Health shows one of three results for each domain:

• Listed — the list it names had your domain on it when we last checked.
• Clean — neither list had your domain on it when we last checked.
• Not confirmed — our check didn’t get an answer that time. This is not a listing; we ask again automatically.

How often we check: a domain we haven’t checked before is checked first. After that, a listed domain is re-checked every 2 hours and a clean one every 12 hours.

What these lists are

Spamhaus and SURBL are independent organisations, and theirs are two of many such lists, each with its own rules for adding and removing entries. Their domain lists track domain names — the part after the @ in an email address, and domains that appear in links — not the servers mail travels through. SURBL lists domains that appear inside emails: in links and text, and as the sender’s domain.

SURBL’s own lists page says its ABUSE list covers “general abused sites” and is built from SURBL’s own research, from records of domain lookups seen across the internet, and from the lists of registered domains that domain registries keep.

Some spam filters check these lists when they judge a message that contains a listed domain; many don’t. So a listing doesn’t stop your mail by itself. To see how your mail is actually landing, open the Warmup page and look at the “Where your warmup emails landed” card.

Why a domain can be listed without any wrongdoing

A domain that’s only days or weeks old can be listed even when it has sent nothing but wanted email. Common, innocent reasons:

• It’s newly registered. Lists use their own data. SURBL says its abuse list draws partly on the lists of registered domains that registries keep, so a domain can be judged early in its life, before it has much history.
• A previous owner. If someone else used the domain name before you, an older listing can linger.

Did warmup cause this?

It’s the first thing most people ask, and you deserve a straight answer rather than a reassuring one. Only the list knows exactly why it added your domain. What you can check is the timing:

• Listed on our very first check. Our first check of a newly connected domain usually runs within an hour or two of connecting. If it already found the listing, ask us and we’ll compare that time with when warmup sent its first email.
• Listed later. If your domain read Clean for a while and then turned Listed, look at what changed on that domain around that time — new campaigns, new links in your emails, or other sending from the domain — and read what the list’s lookup page says about it.

SURBL has told senders it won’t consider a removal request while synthetic warmup or cold outreach from the domain is still running, which is why the removal steps below start with pausing both.

Not sure when the listing first appeared? Email [email protected] with your domain and we’ll look at what our checks recorded for it.

While your domain is listed

• Domain Health keeps showing the listing and re-checks it every 2 hours, so you’ll see when it clears.
• Warmup and campaigns are not paused automatically. They keep running until you pause them.
• Pause them yourself before you ask for removal. SURBL has said it won’t consider a removal request while warmup or cold outreach from the domain is running, so pause warmup and any campaigns on that domain, and keep warmup off until the list decides.

How to check other lists

Domain Health covers Spamhaus DBL and SURBL. To check other lists, use a free public lookup such as MXToolbox, which checks many lists at once — any reputable checker will do. Check both your domain and the mail host you send through, since a listing can be tied to either, and note exactly which list flagged you: that’s the one to contact.

How to ask for removal

1. Look up your domain on the list that named it. Domain Health tells you which list it is. Use that list’s own lookup — SURBL lookup or Spamhaus domain check — and read what it says about your domain. For any other list, the public lookup result usually links straight to it.
2. Pause warmup and campaigns on that domain, and keep warmup off until the list decides. On the Warmup page, switch off the Enabled toggle for each mailbox on that domain (or tick them all and click Disable). On the Campaigns page, open the ⋮ menu (three dots) on each campaign that sends from those mailboxes and choose Pause Campaign. If an AI agent runs your outreach, it sees the listing when it checks a mailbox, and you can ask it to pause those campaigns and switch warmup off.
3. Fix the cause the list points to. Deal with whatever the lookup or the list’s site describes before you submit.
4. Submit through the list’s own form. It’s often labelled “delist”, “removal” or “request review”. Fill it in honestly. Only the list can remove a listing, and WarmySender can’t ask on your behalf — the request has to come from you. Each list runs its own process and timing.
5. When the list has decided. We re-check listed domains every 2 hours, so Domain Health turns Clean soon after the list removes you. Then switch warmup back on and choose Resume Campaign on your campaigns when you’re ready.

Why passing SPF, DKIM and DMARC helps

SPF, DKIM and DMARC are settings on your domain that prove your email really comes from you. Having all three set up and passing is a strong positive signal that your domain is a genuine, properly configured sender. They won’t remove a listing on their own — only the list can — but they’re worth having in place before you ask, and they help your mail land in the inbox generally. Domain Health shows each of them next to the blocklist result.

Frequently asked questions

Will this stop my emails?

Not by itself. Some spam filters check these lists when they judge a message that contains a listed domain; many don’t. To see how your mail is actually landing, open the Warmup page and look at the “Where your warmup emails landed” card.

Does a listing mean I did something wrong?

Not necessarily. Each list uses its own data — SURBL, for example, says its abuse list draws on its own research and on the lists of registered domains that registries keep — so a newly registered domain, or one carrying a previous owner’s history, can be listed. It’s a flag, not a verdict.

Did warmup cause this?

Only the list knows exactly why it added your domain. What we can tell you is the timing: our first check of a newly connected domain usually runs within an hour or two of connecting, and we can compare when we first saw the listing with when warmup sent its first email — just message us. SURBL has said it won’t consider a removal request while synthetic warmup or cold outreach from the domain is still running, so pause both before you ask.

Does WarmySender pause warmup when my domain is listed?

No. Domain Health keeps showing the listing, but warmup and campaigns keep running until you pause them. Because SURBL has said it won’t consider a removal request while warmup or cold outreach from the domain is running, pause both on that domain yourself before you ask, and keep warmup off until the list decides.

Can WarmySender get it removed?

No. Only the list itself can remove a listing, and WarmySender can’t request removal for you. The request goes through the list’s own form — the steps on this page walk you through it.

What does “Not confirmed” mean?

Our check didn’t get an answer that time. It is not a listing. We ask again automatically, usually within a few hours, and Domain Health updates on its own.

Should I switch to a new domain?

Not as a fix. SURBL judges how a domain is used, so moving the same outreach to a new look-alike domain doesn’t fix anything — and SURBL has criticised using look-alike domains for outreach. Pause, fix the cause and ask for removal instead.

Related guides

• Understanding your warmup Inbox Rate — how to read where your warmup is landing
• Why is my mail going to spam when my SPF, DKIM and DMARC look correct? — when all three pass but placement is still poor
• Provider-side blocks: Outlook, Gmail, Yahoo — when an email provider itself restricts a mailbox
• Why are my campaign emails being rejected? — the two kinds of rejection and how to tell them apart
• All documentation