3 Big Mistakes That Are Killing Your Email List (And How to Fix Them Fast)

Woman holding a clipboard with "3 Big Mistakes" written on it, emphasizing common email list errors and solutions for marketers.

by | Mar 26, 2026 | Email Marketing Strategy

This blog is to help you dodge the three BIGGEST mistakes I see all the time from small business email marketers. 

They’re email-list-killers. Revenue-destroyers where your email marketing is quietly failing but you think everything’s fine. Yikes!

Here’s why this matters: 

Email marketing should be making you money.

Around 30% of revenue for most businesses comes through email. But if you’re falling into any of these common howlers, that’s not happening – because you’re accidentally killing your list without even realising it.

I’m Kay Peacey, founder of Slick Business, and I’ve spent years helping small businesses fix exactly this stuff. It’s easily fixed – so that’s great! 

This blog is for you if:

You’re secretly worried you’re not doing email marketing right – because it’s not showing you much love right now in the revenue generating department!

Let’s get into it…

Follow these steps to rescue your email marketing from certain death – with Kay Peacey

Watch Kay Peacey on the 3 big email marketing mistakes to avoid – 10 mins

Why this matters: email marketing is worth 30% of your revenue

Let that sink in for a moment.

If you’re not doing email marketing properly, calculate now how much money you’re losing.

And if you think you’re doing email marketing but your optins are broken, your domain authentication is flaky, and you’re not sending regularly… that’s almost worse. Because you’re putting in effort, thinking you’ve got this sorted, while quietly killing your list in the background.

That makes me sad. So please don’t do it.

Email Mistake 1: Your email optins are broken

Oh, this one drives me crazy to see – and I cannot tell you how many times this happens!

Real example: I just now tested the email opt-ins for a group of smart, revenue-driving business owners recently; people running six and seven figure businesses… 

Out of the four, only one optin actually worked and resulted in me getting emails in my inbox.

That’s not unusual – around 75% of email opt-ins out in the real world are broken in some way 😱

What happens when your email optin is broken

Someone tries to sign up for your list – maybe they want your lead magnet, maybe they just want to hear from you. They put in their email address, hit submit, and then… nothing.

No welcome email. No freebie lead magnet. No welcome. Just silence.

You’ve ghosted them. And then they feel sad 😢

5 things that can break email optins

There are the most common problems that cause email optin failure:

  1. You set optin automation up to send a welcome email but it stopped working and you didn’t notice
  2. No automated process was ever connected to your email optin in the first place – yikes!
  3. You changed your email system (eg moving from MailerLite to ActiveCampaign) and forgot to update your optins
  4. It’s a double optin and the confirmation email isn’t arriving (very common!)
  5. Your email sending domain isn’t authenticated (more on that in a minute)

Either way, the person who just tried to join your world didn’t make it in. And you have no idea it’s happening.

How to test your email optins – today!

I mean it. No excuses – go test them now.

Go to your website. Find each place someone can opt in – footer signup, pop-up, lead magnet landing page, contact forms… 

Test each email optin with a fresh email address.

Does what you think will happen actually happen?

At a minimum, a new subscriber should receive an email within 5-10 minutes of signing up. If they don’t, you’ve got a broken optin.

Speaking of optins… you can join our email list here

Email Mistake 2: Your sending domain isn’t authenticated

If your email sending domain isn’t properly authenticated, your emails might not even make it to the inbox. 

I don’t mean they land in spam or promotions – I mean they never arrive at all.

The mailbox providers (aka the guardians of the inbox – Gmail, Yahoo, Outlook and friends) are protecting people from spam. If your sending domain doesn’t have the right authentication in place, they don’t trust you. And if they don’t trust you, they might just… not deliver your emails.

Poof. Gone. Like they never existed.

What is email domain authentication?

Think of domain authentication as a set of special badges that says: “This email is genuinely from who it says it’s from. This is not a #SkankySpammer pretending to be Slick Business. This is actually Slick Business.”

The technical bits are called SPF, DKIM, and DMARC. You don’t need to know what those stand for. You just need to know whether yours are set up properly.

How to check your email sending domain authentication

Here’s a quickest way to find out:

  1. Send an email from your email marketing system to a Gmail inbox (make a free one if you need to)
  2. Open the email in Gmail
  3. Click the three little dots (the “vertical ellipsis” if you want to sound fancy)
  4. Choose “Show original”
  5. Look for SPF, DKIM, and DMARC
  6. You want to see: PASS, PASS, PASS
Illustration of email marketing mistakes impacting list growth, highlighting the importance of avoiding common errors to improve engagement and deliverability.
Visual representation of common email list mistakes that can harm your marketing efforts, emphasizing the need for proper strategies to grow and maintain an engaged subscriber base.

If you don’t see passes on all three, you’ve got an authentication problem that needs fixing. Your emails are going out without their badge, and the inbox guardians are suspicious.

We’ve made a video and blog on how to check your domain authentication if you want it more step by step.

Want to see what good email domain authentication looks like?

Go sign up for our email list. When the email lands, do the “show original” check. You’ll see pass, pass, pass.

We walk the walk on this stuff.

Email Mistake 3: You’re not sending regular newsletter-style emails

I’ve heard every excuse in the book for this one.

And I get it – I really do. But if you’re not sending regular emails, you’re leaving your email list to go stone cold, and throwing away the chance you had to build know + like + trust, and to get the sales from that relationship.

What counts as “regular” email sending?

  • Weekly – ideal
  • Every two weeks – acceptable
  • Monthly – not regular enough. That’s only 12 emails a year – not enough to get seen.

A regular email (sometimes called an email newsletter, but really it’s just… an email you send regularly) keeps you in your subscribers’ world.

 It keeps you top of mind. It builds the know, like and trust that makes people buy from you when you have something to sell.

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What happens when you don’t send regular emails (aka a newsletter)

Someone signs up for your list. Maybe your opt-in even works (hooray!). Your authentication is solid (gold star!). But then… you just don’t email them.

Weeks go by. Months, maybe.

They forget who you are. They wonder why they signed up. They feel abandoned.

And then one day you pop up in their inbox because you’ve got something to sell. 

You’re back! With a pitch!  This is not a good look.

People don’t like it. They spam report you or they unsubscribe. They definitely don’t buy.

You’re just some stranger who shows up when you want something. That’s not a relationship – it’s an annoyance.

The real barriers to sending regular newsletter emails

Most people think what stops them sending consistent emails is that the tech is too hard. 

It’s not. Hitting send on an email is not technically difficult for people who run whole businesses – that’s the easy part…

The real barriers to email newsletter sending are emotional

Here are the top four reasons I hear for not sending:

  • Fear of unsubscribes – what if people leave?
  • Stress about what to say – what if you’re boring?
  • Feeling like you’re not interesting enough – what if they laugh at you?
  • Time and routine – you just never get round to it

Sound familiar? You’re not alone. I hear these from small business email marketers all the time.

But you need to fix this. Because if you’re not showing up regularly, you’re not building the relationship. And if you’re not building the relationship, you’re not making sales from email.

Come to our Easy Email Newsletter Strategy Masterclass

I know how to fix this for you – like I’ve fixed it for so many small businesses who are now sending regularly without breaking a sweat. I promise you can do it, for real!

In our Easy Email Newsletter Masterclass, I share unique methods that help small business owners and workers get past the emotional barriers, and into a routine of actually sending regular emails.

Emails that feel good to write. Emails people enjoy receiving. Emails that mean when you do have something to sell, people are ready to buy because they already know, like and trust you.

Register here

FAQs – on how to fix your email marketing mistakes

How often should I be sending emails to my list?

Weekly is ideal. Every two weeks is acceptable. Monthly is not enough – that’s only 12 emails a year and it won’t build the relationship you need to make sales. If you’re only emailing when you have something to sell, you’re doing it wrong.

Why are my marketing emails not getting delivered to the inbox?

One possible cause is missing or incomplete sending domain authentication. If your SPF, DKIM and DMARC aren’t set up properly, inbox providers like Gmail don’t trust you – and they might not deliver your emails at all. Check your opt-in process is actually working, today!

How do I check if my email sending domain is authenticated?

Send an email from your email marketing platform to a Gmail inbox. Open it, click the three dots, choose “Show original”, and look for SPF, DKIM and DMARC. You want to see PASS on all three. If you don’t, you’ve got authentication work to do.

My email marketing isn’t converting to sales – what could be going wrong?

If you’re making any of the three big mistakes – broken opt-ins, missing authentication, or not sending regularly – your emails aren’t doing their job. People might not be receiving them, or they’ve forgotten who you are by the time you pitch. Fix the foundations first.

A new lead complained they didn’t get their freebie delivery email – what could be going wrong?

Your opt-in or delivery automation is probably broken. This happens more often than you’d think – something gets disconnected, a double opt-in fails, or your authentication issues mean the email never arrives. Test your opt-in process with a fresh email address and check “show original” for pass, pass, pass.

What are SPF, DKIM and DMARC for email marketing?

They’re the three parts of domain authentication – the technical bits that prove your emails are genuinely from you and not a spammer pretending to be you. You don’t need to understand how they work, you just need to make sure they’re set up and showing PASS when you check. We can help you set these up.

How do I check my email opt-in is working?

Test it yourself with a fresh email address (not one already in your system). Go through the exact process a new subscriber would – fill in the form, hit submit, and see what happens. You should receive a welcome email within 5-10 minutes. If you don’t, your optin is broken.

Why do people spam report my marketing emails?

Assuming you’re not a #SkankySpammer, it could be because you’ve become a stranger. If you only show up when you have something to sell, people feel used. They forgot they signed up, they don’t recognise you, and hitting “spam” is easier than unsubscribing. The fix is to email regularly so you stay familiar and welcome in their inbox.

What should I send in a regular email newsletter?

Think of it as a chit-chat. What’s happening in your world? What’s new? What have you learned? What might be useful or interesting to your subscribers? It doesn’t need to be a big production. A simple, regular email that keeps you top of mind is better than an imagined “perfect” email that never gets sent.

I get signups to my email list but it’s not making sales – why?

Signups are just the start. If you’re not welcoming people properly, staying in touch regularly, and building a relationship, those signups will go cold. Check your optins are working, make sure your emails are authenticated so they actually arrive, and start sending regular emails that build know, like and trust before you try to sell.

Get more help to grow your email marketing ROI

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We can help  you with training and support in the Slick Business Academy. You get access to our Easy Email Newsletter Strategy Masterclass, plus step-by-step training on email deliverability, lead magnet setup, and everything else you need (including moral support and accountability!) to make email marketing actually work for your business.

More importantly, you get support. Real human help from me and the Slick Business team to make sure you actually get things done – and don’t accidentally kill your list while you’re figuring it out.

So come on in to the Slick Business Academy, and you’ll have Kay Peacey and the Slick Business team to guide you every step of the way to more profit and less stress from your email & automation efforts.

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