Seeing a mailbox flagged as "burned," a domain on a blacklist, or a scary spam score can be alarming — but the same word can mean very different things. There are three separate situations here, and each has its own answer. The first step is always to work out which one you're actually looking at.
Situation 1: Smartlead or Instantly shows a "burned" status
Tools like Smartlead and Instantly run their own warmup pools, and a "burned" label usually reflects the rotating IPs inside that tool's pool — not the reputation of your Maildoso domains or mailboxes.
If your mailboxes are active and configured correctly on Maildoso, a "burned" flag in the sequencer is not a sign that your domains have a real reputation problem.
What to do: keep warmup running normally. Don't pause campaigns, don't reduce volume, and don't replace domains based on this label alone.
Tip: check the reputation the dashboard reports for that mailbox instead — see Understanding your mailbox reputation scores (Google Score & Microsoft Score).
Situation 2: A blacklist checker flags your domains (SURBL, Spamhaus DBL) or IPs
Domain blocklists like SURBL and Spamhaus DBL, and IP blocklists that catch one of our rotating sending IPs, are the most common source of scary-looking reports — and none of them mean your domain's reputation is damaged.
In 2026, neither a SURBL nor a Spamhaus DBL listing has any measurable impact on inbox placement at Google or Microsoft business mailboxes. We've tested this repeatedly: properly warmed domains inbox normally whether listed or not, despite what many blogs and checker tools say.
Spamhaus currently lists batches of lookalike or branded domains bought together — a naming pattern, not a reputation problem with your domain or with Maildoso.
What matters is that your SPF, DKIM, and DMARC are passing, which they are on our managed setup.
What to do: keep sending and warming up as usual. There's nothing to fix, no delisting to file, and no need to replace domains — a listing never qualifies for a free replacement, credit or refund.
More detail: SURBL Listings and Deliverability Impact (including Spamhaus DBL) and One of my sending IPs shows as blacklisted.
Situation 3: Google actually rejects your emails, a placement test shows 0% inbox, or you measure a real spam rate on your sends
This one is different. A genuine rejection message from Google, a placement test that consistently shows almost no inbox placement, or a spam rate you've measured across your own campaigns is not just an external checker being noisy — it points to a real issue that should be looked at properly.
What to do: don't ignore it, and don't assume it's a false positive. The fastest route is 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. You can also contact us so our deliverability specialists can review your specific case.
To speed up the review, send us the full headers of one rejected email or a screenshot of the placement test, your account email, the affected domains or mailboxes, and your current warmup settings (volume, reply rate, how long the mailboxes have been warming). Low or too-recent warmup is the most common real cause we find.
Additionally, review your outreach practices to ensure sufficient spintax variation, inclusion of unsubscribe options, and use of clean, well-targeted prospect lists to minimize the risk of spam issues.
A common question: "A checker says my DKIM is missing"
This is normal and expected. DKIM signing for your Maildoso domains is handled on our own sending infrastructure with our own selector, published on the DNS we manage for you. Some external tools only look for a default selector and report DKIM as "missing" even though it's correctly in place — this is by design and follows Google's guidelines. You can confirm everything is in place with a lookup tool that scans all selectors, such as easydmarc.com's DKIM detector. See My DKIM or DMARC isn't detected by a third-party checker. If you're seeing actual rejected emails from Google, that's Situation 3 above — contact us.
Do you guarantee inbox placement?
No, inbox placement depends on factors like sending volume and message content. Maildoso provides tools like IP rotation, reputation scoring, and warmup support to help improve deliverability.
Your dashboard's own reputation view
Your dashboard already gives you a reliable read on mailbox health, so you don't have to rely on a sequencer's "burned" label. On the Email accounts page, and in each mailbox's Deliverability panel, you'll see a Google Score and a Microsoft Score with the date they were last checked. A brand-new mailbox can read low during its first couple of weeks of warmup — that's expected, so let it finish warming up before reading anything into the score. Full explanation: Understanding your mailbox reputation scores (Google Score & Microsoft Score).
Additionally, monitor bounce rates and SMTP-level responses in your sequencer to gain further insights into deliverability performance.
It also helps to know how mailbox rotation is designed to work: individual "burned" mailboxes are meant to take the hit instead of your main domain. If a mailbox does get burned, the recovery is simple — stop sending prospecting emails from it, but keep warming it up. In about 2–4 weeks it recovers. Replacing domains is rarely necessary.
Steps to Recover Burned Mailboxes
1. Stop All Cold Outreach
Immediately pause all campaigns and follow-ups from affected mailboxes. This prevents further damage to their reputation.
2. Implement a Warmup Process
Warmup helps rebuild mailbox reputation by gradually increasing email activity. Follow these guidelines:
Maildoso SMTP Mailboxes:
Warmup: 80 emails/day per mailbox
Reply rate: 45%
No daily increment
Maintain for 1–2 weeks (up to 3 weeks for severe cases)
Google Workspace Mailboxes:
Warmup: 25 emails/day per mailbox
Reply rate: 30%
Increment: 2–3 emails/day
Maintain for 1–2 weeks
After warmup, reintroduce sending gradually, starting with low volumes and increasing slowly.
3. Evaluate Recovery Progress
Monitor mailbox performance during warmup:
Week 1: Too early to judge.
Week 2: Look for slight improvements in placement.
Week 3: If placement remains poor, consider the mailbox permanently burned and replace it.
Mailbox Replacement Policies
If a mailbox is permanently burned, Maildoso memberships allow you to replace it without additional charges. Simply delete the burned mailbox and create a new one in the same slot. Warm up the new mailbox before resuming campaigns.
The key takeaway
"Burned," a blacklist flag, and a real rejection look similar but are three different things. A label inside a sequencer or a blacklist checker (SURBL, Spamhaus DBL, an IP list) almost always reflects rotating IPs or a domain-naming pattern rather than your real reputation, and warmup should simply continue. A genuine Google rejection, a 0% placement test or a measured spam rate on your own sends is the case where you should book a Deliverability Audit or reach out so we can dig into it. When in doubt, contact us with the details above and we'll help you tell them apart.