The 10 biggest mistakes to avoid in cold email
The ones that sink a campaign that was otherwise well targeted and well written, and that support sees every week. Ordered from the most destructive to the most common.
First of all: not having gone through the checklist
The mistake that contains all the others. Clicking launch without having checked your mailboxes, your authentication, your list and your sending limits means discovering the problems once the emails have gone out. And an email that has gone out cannot be taken back.
1. Targeting several people at the same company
This is by far the most expensive one, and the one you see most often with people who have a good file. Targeting three hundred people on the same domain name means targeting a single mail server. And a domain hosting three hundred mailboxes is a large company, so a company with security active by default.
The outcome is almost always the same: the security system spots the burst, especially if the messages look alike, and your emails are stopped before they reach the recipients. The nastiest part is that they do not even bounce. You get no bounce, no alert, nothing to warn you. You simply see an open rate of zero and go looking for the cause somewhere else.
Two or three contacts per company at most, and you look for the right people rather than every person. If you really do need to reach a lot of people at the same company, the only workable route is LinkedIn: there is no corporate mail server between you and the recipient.
2. Launching on brand-new mailboxes and domains
A domain bought the day before and mailboxes created the same day have no reputation at all. Having them send hundreds of emails the next day means showing up at the mail providers with every sign of a throwaway sender.
The trap is that the warm-up score can climb fast and reassure you for the wrong reasons. We saw an account whose mailboxes, created a week earlier on domains of the same age, showed a decent warm-up score and a disastrous inbox placement test, after campaigns launched the day after they were created. Seniority cannot be bought.
Allow two to three weeks of warm-up for a new mailbox, then start the campaign low and ramp up in steps.
3. Forcing the volumes
35 new contacts and 100 emails a day per mailbox, 25 and 75 if the warm-up keeps running: beyond that, you do not gain results, you lose deliverability. To send more, you add mailboxes, you do not push a single mailbox harder.
Two versions of the same excess come up a lot in support. The same mailbox plugged into two campaigns set to 100: limits are set per campaign, with no shared cap, so that mailbox sends 200 emails a day. And a two-hour sending window: Emelia spreads sends over the window you choose, so a short window packs the whole volume into a burst.
4. Asking a question that is too much trouble to answer
Your question is your call to action, since the whole point of the message is to get a reply. If it requires thinking, checking a figure or digging out a file, the person puts it off and never comes back to it.
We see a lot of messages where replying is real work. A question you can answer in one line, from your phone, between two meetings, gets far more responses than a clever but costly one.
5. Not spacing out your follow-ups enough
The right rhythm depends on your country and on what you sell, but following up every day or every other day is pushy in just about every case.
The risk is not only that you annoy people. Someone who gets three messages in a week from a stranger does not unsubscribe, they report you. And a spam report weighs infinitely more on your domain's reputation than an unsubscribe, which costs nothing. Keep a visible unsubscribe link: it is the exit you want them to take.
6. Weighing your email down
An email that lands in the inbox is a light email. Light means short, with no attachment and, if possible, no image.
On images, one nuance: a light image in a signature condemns nobody, and plenty of people are attached to theirs. What is a real mistake, on the other hand, is putting your whole signature in as an image. Three consequences, all bad. The weight goes through the roof. Nothing is clickable any more, not the phone number, not the address, not the website. And since many mail clients block images until the recipient accepts them, your signature stays invisible at the exact moment it was supposed to inspire trust.
As for attachments, replace them with a link. A standard share link does the job. And if your aim is to get a document read, tools like Papermark also show you where the reader stopped, which no attached file will ever tell you.
7. Writing in metaphors
In cold outreach, clarity beats elegance every time. Images, analogies and turns of phrase that circle around the subject force the reader into an effort of interpretation they will not make for a stranger.
The test is simple: reread your message and ask yourself whether what you have just written is clear. Not pretty, not original. Clear.
There is a nuance: in a genuinely personalized message, where an image makes sense for the specific prospect you are targeting, why not. But that is the exception, not the method.
8. Asking ChatGPT to write your cold email
This is the most common cause of the previous mistake. A general purpose model asked for an outreach email produces metaphors, marketing phrasing and a length that kills the message. It does not have the rules of cold email, it has the rules of mass emailing. Some models do better than others, but none of them have those rules natively.
That does not mean going without. It means giving it the rules first. Open the page that explains how to write a cold email, use the Educate my AI button at the top of that page, and paste the result into your conversation before you ask for anything.
9. Not testing your variables and spintax
"Hello ,": that is what contacts with no first name receive, with no error and no warning. Add a misspelled variable, a broken spintax or a dead unsubscribe link, and a whole list receives an obviously automated email.
The fix takes five minutes: the Preview to go through your contacts, then two or three test emails sent from the last step of the sequence. The preview alone is not enough: some cases it shows correctly are broken in the real send.
10. Contacting the same people again without meaning to
Emelia removes duplicates inside a campaign, never between two campaigns, and that is deliberate: you may want to reach someone again. But if you launch a new campaign on a file that overlaps the previous one, the same people get the same first email. Leave out the lists you have already worked with the campaign's Lead exclusion. Good news along the way: when you reuse the same list, bounces and unsubscribes are left out automatically.
The most expensive case we have seen: a list exported mid-campaign, reworked in a spreadsheet, then imported again. Re-imported contacts are new records, even if they keep their old status, and the campaign sent them the first email again: more than two hundred people got it twice. Never delete contacts you have already reached in order to import them again.
Frequently asked questions
The questions we get asked on this topic, answered briefly.
How many contacts per company at most?
Two or three. Beyond that, you are writing in bursts to the same mail server, and large companies filter that kind of wave without sending back a bounce. To reach many people in the same company, go through LinkedIn.
My emails are not arriving, but I have no bounces. How is that possible?
A corporate filter can stop an email without rejecting it: it does not bounce, it disappears. It is typical of a campaign that targets many people on the same domain. Check that first, then the campaign setup and deliverability: see My campaign sends nothing, or a 0% open rate.
Can I send more than 100 emails a day from a single mailbox?
We advise against it. Volumes are set per mailbox: to send more, add mailboxes rather than pushing a single one harder. Also watch out for mailboxes used in several campaigns, whose limits add up.
A contact received the first email twice. Why?
Almost always because they are in two campaigns, or because contacts already reached were deleted and imported again: they are then new records, and the campaign starts them from the beginning. Use Lead exclusion, and never re-import a list you have already worked into the same campaign.