Email Deliverability for Small Teams: Why Emails Go to Spam and How to Fix It

An email can be “delivered” and still never be seen. Delivery only means the receiving server accepted it. Deliverability is whether it reaches the inbox instead of the spam or promotions folder.

Gmail, Outlook and Yahoo decide that for every message based on three things: whether they can confirm the email really came from you (authentication), how people have reacted to your past emails (reputation), and what the email looks like (content). Small teams usually lose deals to the first two, not the third.

• Your domain isn’t authenticated. Without SPF, DKIM and DMARC, inboxes can’t prove the email is from you, so they treat it with suspicion.
• You send from a free address through a tool. Sending as you@gmail.com or you@yahoo.com from a CRM or email platform fails those providers’ own checks. Use your business domain.
• A new or quiet domain suddenly sends a lot. Inboxes are wary of volume with no history behind it.
• Your list has old or bad addresses. Bounces and spam traps tell inboxes you don’t look after your list. Bought lists are the fastest way to the spam folder.
• People mark you as spam. Complaints are the strongest negative signal there is.
• There’s no easy way to unsubscribe, so people use the spam button instead.
• The email looks like a promotion: ALL CAPS, “!!!”, hype words, one big image with little text, lots of links or link shorteners.

These are three DNS records on your domain. Your email tool gives you the exact values; you paste them into your domain provider (GoDaddy, Cloudflare, Namecheap and so on).

• SPF lists the services allowed to send email for your domain. If you use more than one tool (your inbox, your CRM, your newsletter tool), all of them belong in the one SPF record.
• DKIM adds a signature to each email that proves it wasn’t changed and came from your domain. Each sending tool gives you its own DKIM record.
• DMARC tells inboxes what to do when SPF or DKIM fails, and sends you reports. Start with p=none so nothing is blocked while you check the reports, then tighten it later.

Once all three pass, most of the “why is this in spam?” problems for a small team go away.

Since 2024, Gmail and Yahoo require bulk senders, roughly anyone sending around 5,000 emails a day to their users, to meet a set of rules. Microsoft added similar rules for Outlook and Hotmail in 2025. Non-compliant email gets sent to spam or rejected.

• Authenticate with SPF and DKIM, and publish a DMARC record that lines up with the domain in your “From” address.
• Offer one-click unsubscribe on marketing email, and honor requests quickly (within two days).
• Keep spam complaints below 0.3%, ideally under 0.1%.

Most small teams send far less than 5,000 a day, but the same checks feed every inbox’s filters, so meeting them is the simplest way to stay out of spam at any volume.

Inboxes keep score on your domain. Opens, replies and “not spam” clicks raise it; bounces, complaints and ignored emails lower it.

• Warm up new domains. Start with a small number of emails a day to people likely to reply, then increase gradually over a few weeks. Warm-up tools can help with this.
• Keep volume steady. A sudden spike from 20 emails a day to 2,000 looks like a hacked or spam account.
• Separate risky sending. If you do cold outreach, send it from a separate subdomain or domain so a bad week doesn’t hurt the email your customers rely on.
• Replies are gold. A question that invites a reply does more for reputation than any trick.

• Never buy or rent lists. They are full of dead addresses and spam traps.
• Remove hard bounces right away, and stop emailing addresses that keep soft-bouncing.
• Stop emailing people who never open. After a few months of silence, send one “still interested?” email, then remove them.
• Honor unsubscribes everywhere. Someone who unsubscribed from your newsletter shouldn’t keep getting your sales sequence.
• Check new addresses from forms for typos (gmial.com) before they bounce.

• Write like a person. Sales emails that look like a note from a colleague do better than designed newsletters.
• Keep the subject calm: no ALL CAPS, no “!!!”, no “RE:” on an email that isn’t a reply.
• Limit links to one or two, on your own domain. Skip link shorteners.
• Balance images with text. An email that is one big image is a classic spam pattern.
• Watch your words. “Free”, “guaranteed” and “act now” are fine once in a genuine email; stacked together they read as spam.
• Include your business address and an unsubscribe line on marketing email.

Paste any template into our free email spam checker before you send it. It underlines risky words, checks your subject line, links and unsubscribe line, and gives the email a grade out of 100.

• Replies dry up on emails that used to get answers.
• Bounce rate climbs above a couple of percent.
• Open rates drop suddenly across the board (though opens are less reliable than they used to be, because some email apps preload images).
• Google Postmaster Tools shows problems with your domain’s authentication or spam rate.
• Test sends land in spam. Send to your own Gmail and Outlook addresses and check where they land.

1. You send from your own domain, never a free Gmail or Yahoo address.
2. SPF, DKIM and DMARC are set up and passing for every tool that sends as you.
3. New domains are warmed up gradually; volume stays steady.
4. Cold outreach goes from a separate subdomain or domain.
5. Every contact opted in or has a real business reason to hear from you. No bought lists.
6. Hard bounces are removed; long-silent contacts are cleaned out.
7. Marketing email has a one-click unsubscribe and your business address; unsubscribes are honored everywhere.
8. Templates are checked before they go out, and subject lines are calm.
9. You watch replies, bounces and spam complaints, and keep complaints under 0.1%.

• Your own sending domain: add it in settings, add the DNS records Conduyt shows you, and click Verify.
• Replies land on the contact’s timeline once reply capture is set up, next to calls and texts.
• Unsubscribes are built in: marketing emails carry an unsubscribe link plus the one-click unsubscribe headers Gmail and Yahoo look for, and Conduyt won’t send marketing email to a contact who opted out.
• Warm-up and newsletters: connect Warmy for inbox warm-up, or sync lists to Mailchimp, which sends unsubscribes and bounces back to Conduyt.

For the texting side of the same problem, see our SMS compliance guide.