Cold email mistakes I've seen sink campaigns over 12M emails

Over six-plus years and about 12 million emails, I've watched campaigns fail in every way you can imagine, some of them mine. Most failures come from three things: bad lists, deliverability problems and weak offers. Nearly every mistake below belongs to one of them.

List mistakes

1. Emailing everyone who might buy

"Small businesses in the US" isn't a list. The tighter the niche, the more the email feels written for that person. Start with one industry, one job title and one problem.

2. Not verifying

Unverified lists bring bounces, and bounces damage your domains. Verify right before sending, and keep bounces under 2%.

3. Sending old lists

People change jobs all the time. A list that's been sitting for months has decayed, even if it was clean once.

Deliverability mistakes

4. Sending from your main domain

If that domain gets a bad reputation, your invoices and client emails suffer. Use separate domains and keep the real one safe.

5. Skipping warm-up

Give new mailboxes about 14 days before any campaign. Here's what warm-up does.

6. Too much volume, too soon

Around 30 campaign emails a day per mailbox and three mailboxes per domain. If you need more, add mailboxes instead of raising the number. The numbers are here.

7. Not checking DNS

One broken SPF or DKIM record can send your whole campaign to spam. Check it. It takes a minute.

8. Making it hard to opt out

If you make leaving hard, people use the spam button, and that does far more harm than losing a lead.

Offer and copy mistakes

9. A weak offer

This is the one people least want to hear. If your offer isn't something they want, no subject line will fix it. Before changing the email, ask whether you'd say yes to it yourself.

10. Talking about yourself

"We are a leading provider of…" tells them nothing. Lead with their problem. Here's how I write them.

11. Long emails

They read it on a phone, between other things. If it needs scrolling, it's too long.

12. Asking for too much

A 30-minute demo from a stranger is a big ask. "Worth a look?" or "Should I send more?" is easy to say yes to.

13. No follow-ups

I send one email and three follow-ups, waiting 3, 5 and 7 days. Why that timing.

14. Fake personalisation

"I loved your recent post" with nothing specific fools nobody. A plain email beats a fake one.

Process mistakes

15. Judging by opens

Open rates mislead. Judge by replies and meetings.

16. Giving up too early, or changing everything at once

Fifty emails isn't a test. Send to a few hundred people, change one thing, and compare.

17. Being slow to reply

You've done all that work, and then an interested reply sits for two days. Answer quickly, because that's where the money is. See turning replies into meetings.

18. Sending into a country without checking the rules

The law differs by country, and sometimes by a lot. Read the summary, then ask a lawyer where it matters.

If you're starting from zero, the first campaign in 30 days playbook walks through the whole order.