Why Is My Mailbox In Quarantine?
Understanding the quarantine phase and how to get your mailbox back to sending
Quick Answer
Your mailbox is in quarantine because it was auto-paused and the cooldown period has expired. The system is now checking if your domain’s DNS is healthy before allowing any sends. If DNS checks pass, your mailbox will automatically graduate to the next recovery phase.
What Does Quarantine Mean?
Quarantine is Phase 2 of the auto-healing pipeline. It sits between the initial cooldown pause and the restricted sending phase. Think of it as a health checkpoint — the system needs to confirm your infrastructure is sound before it lets any mail flow again.
Where Quarantine Fits in the Pipeline
What Is the System Checking?
During quarantine, Superkabe runs a full DNS health audit on your mailbox’s domain. All checks must pass before the mailbox can move forward.
SPF Record
Verifies that your domain’s SPF record exists and includes the sending servers you use. A missing or misconfigured SPF record means receiving servers can’t trust your mail.
DKIM Record
Confirms your DKIM signing key is published correctly. DKIM proves that emails haven’t been tampered with in transit. Missing DKIM significantly increases spam placement risk.
Blacklist Check
Scans major blacklists (Spamhaus, Barracuda, SORBS, SpamCop) for your domain and sending IPs. Being listed on any of these will block delivery to large portions of the internet.
What Keeps a Mailbox Stuck in Quarantine?
Your mailbox will remain in quarantine indefinitely until the underlying issues are resolved. Common blockers:
- • Missing or broken SPF record — Your DNS provider may have overwritten it, or you exceeded the 10-lookup limit
- • Missing or invalid DKIM record — The DKIM key wasn’t published, or it doesn’t match what your sending platform expects
- • Domain is blacklisted — Your domain or IP appears on one or more major blacklists
- • DNS propagation delay — You fixed the record but it hasn’t propagated yet (can take up to 48 hours)
How to Fix It
Step 1: Check Your DNS Records
Log into your DNS provider (Cloudflare, Namecheap, GoDaddy, etc.) and verify:
- • SPF record exists as a TXT record on your root domain
- • DKIM record exists as a TXT or CNAME record (check your sending platform for the exact selector)
- • No conflicting or duplicate records
Step 2: Check Blacklist Status
Use a tool like MXToolbox or multirbl.valli.org to check if your domain or IP is listed. If listed:
- • Visit each blacklist’s website and submit a delisting request
- • Spamhaus and Barracuda typically delist within 24–48 hours after request
- • SORBS may take longer — follow their specific process
Step 3: Wait for the Next Check
Superkabe periodically re-checks quarantined mailboxes. Once your DNS is clean and blacklist removals have propagated, the system will automatically graduate your mailbox to the restricted_send phase on its next check cycle.
How Long Does Quarantine Last?
DNS is healthy: If SPF, DKIM, and blacklist checks all pass, the mailbox graduates immediately on the next check cycle.
DNS recently fixed: If you just corrected a record, allow up to a few hours for propagation and the next system check.
Unresolved issues: If DNS is broken or domain is blacklisted, the mailbox stays in quarantine until you fix the underlying problem.
What Happens After Quarantine?
Once all DNS checks pass, your mailbox graduates to Restricted Send (Phase 3). In this phase:
- • Warmup is re-enabled at a very low volume (5 emails/day)
- • Every send is monitored for bounces
- • The mailbox must achieve 10–20 consecutive clean sends to graduate further
- • Any bounce during this phase resets progress
The goal: Prove the mailbox can send cleanly before ramping volume back up.
Common Mistake
Do not try to manually re-enable or force-send from a quarantined mailbox on your sending platform (Smartlead, Instantly, etc.). Superkabe has already removed it from active campaigns for a reason. Sending from a quarantined mailbox bypasses the healing pipeline and can cause permanent reputation damage.