Why Are My Cold Emails Going to Spam? 12 Causes and How to Fix Them

You wrote a good email, loaded a good list and hit send. Then the replies never came, because most of your emails went straight to spam. It happens to almost every cold emailer at some point, and the cause is nearly always one of the twelve below.

First, check where you actually land. Send a blank email from the affected inbox to our free inbox placement test and you will see whether it reaches the inbox, promotions or spam. Then work through this list from the top. The first five cause most problems.

1. SPF, DKIM or DMARC is missing or broken

These three DNS records prove your emails really come from your domain. Gmail, Yahoo and Microsoft now expect all three from anyone sending at volume, and treat mail without them as suspicious. A single typo in an SPF record is enough to fail.

Fix: make sure all three exist and pass. Our SPF, DKIM and DMARC setup guide walks through it, or use mailboxes that come with them configured.

2. The domain or inbox is brand new and cold

A mailbox created yesterday has no reputation. If it starts sending 100 cold emails a day, providers treat it exactly like a spammer would look.

Fix: warm new inboxes for two to four weeks before campaigns. See how long email warmup takes.

3. You send too much from each inbox

Even a warm inbox gets flagged if volume jumps. Google Workspace technically allows 2,000 emails a day, but cold email works best far below that.

Fix: cap each inbox at 30 to 50 cold emails a day, follow-ups included, and add more inboxes instead of more volume. See Google Workspace sending limits.

4. Your list bounces

Bounces tell providers you are emailing addresses you do not know. A bounce rate above 2 to 3% damages reputation fast, and some sequencers pause campaigns at 5%.

Fix: verify every list before sending, remove catch-all and role addresses you cannot verify, and never reuse old lists. Our bounce code guide explains what each error means.

5. You are sending from your main domain

When cold email hurts your main domain's reputation, your invoices, support replies and team email start landing in spam too.

Fix: send cold email from separate lookalike domains (for example getacme.com or tryacme.com) that redirect to your website.

6. Recipients mark you as spam

Gmail wants your spam complaint rate below 0.1% and treats anything approaching 0.3% as a serious problem. A handful of complaints on a small campaign can cross that line.

Fix: tighten targeting, make it easy to opt out with one line ("not relevant? just reply and I won't follow up"), and stop sequences after a clear no.

7. Link and open tracking on a shared domain

Most sequencers rewrite links through a shared tracking domain. If someone else on that domain sends spam, you inherit their reputation.

Fix: set up a custom tracking domain, or turn off open and click tracking for first emails. Many teams measure replies only.

8. Too many links, images or attachments

Cold emails with several links, a logo, an image signature or a PDF look like marketing blasts.

Fix: plain text, at most one link, no attachments in the first email. Send the deck after they reply.

9. Spammy wording

Modern filters care more about engagement than keywords, but "free", "guarantee", "act now", lots of capitals and exclamation marks still add risk.

Fix: write like one person emailing another. Short, specific, no hype. Our subject line guide helps with the first line they see.

10. Every email is identical

Sending the same 120 words to thousands of people creates a pattern filters can spot.

Fix: personalise the first line, use spintax or a few variants, and keep segments small and relevant.

11. Your domain or IP is on a blacklist

Listings on Spamhaus, Barracuda or UCEPROTECT can send mail to spam or get it rejected outright.

Fix: check the major lists and follow the removal process. See our blacklist removal guide.

12. Nobody engages with your emails

Inbox providers watch what recipients do. Emails that are never opened, replied to or rescued from spam slowly drag reputation down.

Fix: keep warmup running alongside campaigns. It adds a steady stream of opens, replies and "not spam" signals. See how inboxy warmup works.

The quick version

• Authenticate every domain with SPF, DKIM and DMARC.
• Use separate domains, two or three mailboxes each.
• Warm every inbox for two to four weeks, then keep warming.
• Send 30 to 50 emails per inbox a day, to verified lists only.
• Plain text, one link at most, real personalisation.
• Test placement before every launch.

Skip the setup

inboxy creates Google Workspace mailboxes with SPF, DKIM and DMARC already configured, connects them to your sequencer for free and keeps them warm, at a flat $3 per mailbox a month. See pricing.