How to Fix Low Inbox Delivery Issues in Cold Emails
Cold emails not landing in the inbox? Here’s how to fix low delivery rates and avoid spam filters fast.
Last updated
Cold emails not landing in the inbox? Here’s how to fix low delivery rates and avoid spam filters fast.
Last updated
Cold email is one of the most powerful tactics — if your emails reach the inbox. But inbox filters are getting more aggressive, and cold senders are often the first to be penalized.
If your cold emails are getting ignored, landing in spam, or not delivering at all, don’t worry — this guide will show you how to identify and fix the most common problems quickly.
This is where most cold emailers go wrong. If you skip setup, you’re likely flagged before your first email even goes out.
Checklist before sending cold emails:
✅ Custom sending domain (avoid Gmail or Outlook personal accounts)
✅ properly configured
✅ Branded, trustworthy “from” name and reply address
✅ Dedicated mailbox for outreach (not your main domain)
Pro tip: Use subdomains like
mail.yourcompany.comspecifically for cold email campaigns.
Sending cold emails from a “cold” domain or IP? That’s an instant red flag to inbox providers.
Fix it:
Start with low volume (10–20/day)
Gradually increase over 3–4 weeks
Prioritize sending to real, engaged inboxes (warm leads, colleagues, etc.)
Sending to scraped or outdated lists full of:
Invalid emails
Spam traps
Role-based accounts (admin@, info@, etc.)
Solution:
Remove catch-all or risky addresses
Segment based on industry, intent, or title for better relevance
Spam filters are trained to detect “cold email patterns.”
Avoid:
“Hi, I’m reaching out because…”
Overused phrases like “quick call,” “increase revenue,” “limited offer”
Long intros, heavy formatting, and large images
Do this instead:
Use 3–5 short sentences
Make it about them, not you
Use a personalized intro line based on their website, role, or business
Inbox providers notice repetition. They flag emails that look identical over time.
What to rotate:
From name
From email address
Subject line
Opening sentence or value pitch
Signature and CTA
Don’t assume your emails are landing where you want. Test regularly using tools like:
Mail Tester
InboxAlly
GlockApps
SenderWiz (includes inbox and reply monitoring)
Also track:
Open rate by provider (Gmail, Outlook, etc.)
Spam complaint rate
Domain/IP reputation
Bounce rate
Cold email success isn’t about blasting more — it’s about getting more positive signals from each campaign.
Try this:
Ask simple questions to generate replies
End emails with soft CTAs (“Is this relevant?” instead of “Book a demo”)
Use personalized PS lines or links
Cold email is a long game. If you cut corners on setup, content, or sending strategy, you might get a few leads — but your domain will burn out fast.
Instead:
Build trust gradually
Send value, not volume
Monitor your setup like a pro
📬 When your email looks like it’s written for a real person (because it is), you’ll see higher open rates — and better results.
Use like SenderWiz to simulate opens, replies, and inbox behavior
…can destroy your in days.
with an email validation tool
Learn more about .
SenderWiz users can across their cold campaigns, which helps each email feel more one-to-one.
Explore to improve tracking and decision-making.
Inbox algorithms LOVE replies — they’re one of the strongest inbox placement signals. Discover more in our .
Use tools designed for inbox success — like