Landing in spam is rarely bad luck. It is usually one of five fixable causes. Work through them in order, because the earlier ones matter most.
1. Broken or missing authentication
If your domain has no SPF, DKIM, or DMARC records, receiving servers cannot confirm the mail is really from you, and modern filters treat that as suspicious by default.
This is the first thing to fix and the easiest to get wrong. A common trap: a valid-looking DMARC record with SPF or DKIM that is not aligned to your From domain. Walk through our SPF, DKIM, and DMARC guide and confirm all three pass before touching anything else.
2. A cold domain sent hot
A brand-new domain, or an old one that has never sent much, has no sending history. When it suddenly pushes 50 or 100 emails a day, filters read that as a spam pattern and quarantine it.
The fix is a warm-up ramp: start with a handful of emails a day and increase gradually over two to four weeks so mailbox providers build a positive history for your domain. Skipping this is the single most common reason new senders burn a domain. Our email warm-up guide covers the schedule in detail.
3. Content that trips filters
Assuming authentication and warm-up are handled, content is next. Filters and recipients both react to how the email reads:
- Spam-trigger language: “free,” “guarantee,” “act now,” excessive exclamation marks, and all-caps subject lines.
- Image-heavy or link-heavy mail: a single tracking link in a short personal note is fine. A wall of images with three CTAs is not.
- Bulk-looking templates: identical text sent to hundreds of people reads as bulk. A genuine one-to-one email personalized to the recipient does not.
- Broken formatting: HTML that does not render, or a huge signature block, drags trust down.
Write like a person emailing one other person. See our cold email best practices for the specifics.
4. Too much volume, too fast
Even a warmed domain has limits. Push past a few dozen emails per mailbox per day, or ramp volume in sudden jumps, and providers throttle you. Sending in a tight burst at the same second also looks automated.
Send at a human pace, spread across the day, and scale by adding mailboxes rather than cranking one inbox to its limit. We cover the exact numbers in how many cold emails per day.
5. A damaged reputation
Reputation is the score mailbox providers assign your domain and IP based on past behavior. It drops when you:
- Hit spam traps (dead addresses that only spammers reach).
- Get high bounce rates from stale or scraped lists.
- Send to people who mark you as spam.
- Ignore opt-outs and keep emailing people who asked you to stop.
Clean your list before sending, remove invalid addresses, and honor every opt-out permanently. Reputation is slow to build and fast to lose.
How PitchButler prevents this
Most spam problems come from sending too much, too fast, from an unauthenticated or cold domain. PitchButler is built to avoid exactly that: a warm-up ramp so your domain is never sent hot, daily SPF, DKIM, and DMARC checks, one-to-one emails at a human pace instead of bulk blasts, permanent opt-outs, and a kill switch that pauses sending automatically if bounce or spam rates spike.
That is the whole point of an AI SDR with manners: the tool protects your reputation so you do not have to babysit it. See how it works or the safeguards on our security page.