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Deliverability Troubleshooting

Deliverability is the most frustrating topic in outbound. You send well-written messages to a tight ICP, and half land in Spam. This guide helps diagnose and fix.

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How to Spot a Problem

3 number-based indicators: If one or more metrics is in “Problem” — take a step back. Don’t send more messages until you understand why.

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Step-by-Step Diagnosis

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Step 1 — Check mail-tester

This is the most important check. Send one email from Link AI to the mail-tester.com address, and open the report. You want to see:
  • 9/10 or 10/10 overall score
  • SPF: pass
  • DKIM: pass
  • DMARC: pass
  • Sender reputation: green
  • Content score: 100%
If you’re below 8 — you have a setup issue. Fix it before continuing.

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Step 2 — Check DNS Records

At mxtoolbox.com:
  1. SPF Lookup on your domain → ensure there’s exactly one record, and that it includes the right server:
    • Google Workspace: include:_spf.google.com
    • Microsoft 365: include:spf.protection.outlook.com
  2. DKIM Lookup → check the selector (usually google._domainkey or selector1._domainkey)
  3. DMARC Lookup → make sure a policy exists (even p=none beats nothing)
Common mistake: two SPF records on the same domain. This breaks authentication. You need one record that combines all includes.

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Step 3 — Check Sender Health in the Dashboard

Settings → Senders → [Your Sender] → Health Check You’ll get a report with:
  • Domain reputation (Google Postmaster Tools score)
  • Recent bounce trend
  • Recent spam complaint trend
  • Warmup status
If anything’s red — start there.

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Fixes by Symptom

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”Open rate under 25%”

Likely causes, most common first:
  1. Insufficient warmup — if this is a new sender (under 30 days), restart warmup for another 21-30 days. Don’t send big volume until it finishes.
  2. Subject line — if the subject feels “spammy” (ALL CAPS, exclamation marks, words like “FREE”, “URGENT”), it hurts deliverability. Let Link AI write subjects (default), don’t force a specific subject.
  3. Volume scaled too fast — if you went from 10/day to 100/day with no gradual ramp, providers flag you as suspicious. Drop to 30/day for 7 days, then 50, then 100.
  4. Domain reputation hit — if you were at 95% open rate and now you’re at 15%, something hit reputation. Send less and check Google Postmaster Tools.

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”Bounce rate over 7%”

This is a lead quality issue, not a setup issue.
  1. Check ICP — are you targeting companies that are still active? Sometimes enrichment returns dead companies.
  2. Check email validation — Link AI validates emails, but sometimes stricter validation helps. If bounce rate is consistently high — contact us and we’ll review.
  3. Don’t keep sending — bounce rate above 10% damages reputation within 48 hours. Pause the campaign, fix it, then resume.

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”Spam complaints over 0.3%”

This is the most serious. Every complaint hits domain reputation.
  1. ICP too broad — if you’re sending to “anyone in sales”, some will mark as spam. Tighten to a sharper ICP.
  2. Aggressive tone — consultative or casual get fewer complaints than direct with certain audiences.
  3. Unclear unsubscribe — Link AI adds a footer with opt-out automatically. If you removed it — bring it back.

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”Mails in Spam folder (not Inbox)”

We can’t see this from our reports — we see opens, not location. But if someone reports it:
  1. Ask a trusted recipient (client, friend) to add you to contacts and mark “Not spam”
  2. Make sure you’re sending from a domain with DMARC p=quarantine or stronger
  3. If 50%+ of mails are in Spam — stop, restart warmup for 14 days

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When to Build a Fresh Sender

If domain reputation took a serious hit (most mails in Spam, high complaints), it’s sometimes better to start fresh:
  1. Buy a new domain — option: a domain “alias” like linkaiil.io if your primary is linkaiil.com
  2. Configure SPF/DKIM/DMARC fresh — per Sender Setup
  3. Connect to Link AI and wait 30 days of warmup
  4. Start at low volume — 20/day for 2 weeks, then 50
The old domain stays for your primary purpose (website, marketing). Outbound moves to the new domain.

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When to Contact Support

Reach out if:
  • Metrics stay red for more than a week despite all the steps above
  • A technical OAuth or sync issue you can’t resolve
  • Suspected bug in Link AI (sudden 0% open rate, sync broken)
  • A reporting question you don’t know how to interpret
The team is available via Dashboard → Help → Contact Support, or mailer.linkaiil.com → Support.

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What’s Next

Sign up to Link AI

Start with a clean sender and green deliverability tier from day one