Seeing your domains flagged on a blacklist can feel like the end of the road — but in practice it almost never is. A blacklist flag is not a verdict: in most cases it either has no real effect on your deliverability at all, or it's something our team can fix or work around. This article explains how we handle blacklist reports, what information we'll ask you for, and where refunds fit into the picture.
A blacklist flag is not a verdict
Blacklist checkers and sequencer warnings look scary, but they very often reflect rotating IPs or domain-reputation lists that mailbox providers no longer use, rather than real damage to your domains. Domain blacklists — both SURBL and Spamhaus DBL — do not affect inbox placement at Google or Microsoft. We know this contradicts a lot of what's written online, but it's what we see in our own tests every time: a properly warmed domain inboxes normally whether or not it is listed. Google stopped using Spamhaus DBL as a spam signal in August 2026, and dropped SURBL the year before; none of the major mailbox providers consume either list today. Most "blacklisted" reports fall into one of these buckets:
SURBL (and similar URL lists like SpamRATS): no measurable impact on inbox placement. Nothing needs fixing and campaigns should simply continue. See SURBL Listings and Deliverability Impact.
Spamhaus DBL (domain list): also no impact on Google or Microsoft placement. We regularly run spam tests on DBL-listed domains and see them inboxing normally. Spamhaus currently lists batches of lookalike or branded domains bought together — a naming pattern, not a reputation problem. Keep warming up at the recommended volume and keep sending; a listed domain that is still new should simply finish its standard warmup before campaigns, as usual. A DBL listing by itself is not a reason to delete, replace, or delist a domain. Full guidance: What about Spamhaus DBL?
A flagged sending IP (Spamhaus CSS/SBL/XBL, Barracuda, and similar IP lists): we rotate sending IPs automatically, and IPs that get listed are rotated out. Some of our pool will always be listed somewhere — that's the nature of high-volume cold-email infrastructure — and it doesn't affect what you send. See One of my sending IPs shows as blacklisted.
A "burned" label in Smartlead/Instantly: usually reflects that tool's own warmup pool, not your Maildoso domains. See My mailboxes show as "burned", "blacklisted", or low reputation.
A real deliverability issue (actual Google rejections, 0% inbox placement, a measured spam rate on your own sends): this is the case our deliverability specialists dig into — and even here there are fixes, from warmup recovery (a burned mailbox typically recovers in 2–4 weeks) to content optimization. The fastest way to get it looked at is a free Deliverability Audit (see below).
If you are seeing actual spam placement on a listed domain — not just the listing — that is a warmup or content question rather than a blacklist question: send us a placement-test result or book a Deliverability Audit and we'll look at it with you.
Send us the details first — even if you're thinking about cancelling
In the large majority of blacklist cases we can help, but we can't tell which bucket you're in without the specifics. So the first thing we'll do is look at your case, and for that we need:
The email address on your account and the affected domains or mailboxes.
Which blacklist or tool flagged them (SURBL, Spamhaus, MXToolbox, Hetrix, a sequencer warning, an audit report — a screenshot helps a lot).
Whether you're seeing actual bounces, rejections or spam placement — if so, the full headers of one rejected email or your placement-test result.
Your current warmup settings and how long the mailboxes have been warming (warmup volume that's too low is the most common real cause we find).
Even if your first instinct is to stop using the product or ask for a refund, please send us these details first. Very often the "blacklisting" turns out to have no real impact (as with SURBL and DBL), or it's fixable within days — and you keep your domains, your warmup progress, and your campaigns.
What we can do for you
Confirm whether there's any real impact — checking your actual placement and reputation rather than a third-party flag.
Fix what's fixable — recovery plans for burned mailboxes, content review, and configuration review.
Run a free Deliverability Audit with our expert: log in, click the Deliverability Audit button in the top-right of your dashboard, and pick a time. This is the fastest route for anything beyond a simple flag.
Replace domains where a domain is genuinely unusable — for example a registrar suspension, or a name our system can't create mailboxes on. A SURBL or Spamhaus DBL listing is not such a case and never qualifies for a free replacement; see Domain replacement.
What we don't do: delisting requests
We don't file SURBL or Spamhaus delisting requests on your behalf, and we don't recommend you spend time on them either — the listing has no delivery effect, so there's nothing to recover. Spamhaus in particular treats any cold outreach as spam by policy and generally won't delist a domain used for it regardless of what you fix. If you'd rather reduce how often your domains get listed in the first place, the single most effective step is choosing unique, generic domain names rather than a batch of lookalikes of your brand — Spamhaus specifically looks for that pattern. See What are the best practices for configuring domains?
Where refunds fit in
A refund is the last resort, not the starting point. It only comes into the conversation after we've reviewed your situation and genuinely couldn't help — and eligibility then follows our standard policy (the 30-day new-customer guarantee and its exclusions), described in Refunds and cancellations. A blacklist flag by itself — SURBL or Spamhaus DBL — is not a reason to refund, replace, or abandon your setup, because it isn't affecting your delivery. Give us the chance to look at your case first: that's the fastest route to your campaigns performing again.