Why is my email going to spam?
Not luck, not a mystery spam-filter mood — almost always one of four specific, checkable things. Here's what they are, in order of how often each one is the actual culprit.
1. No SPF record, or the wrong one
SPF (Sender Policy Framework) is a public list of which mail servers are allowed to send email for your domain. When it's missing, mailbox providers have no way to confirm a message claiming to be from you actually came from somewhere authorized — so they treat it with more suspicion, and spam is the safe default. A common variant of this problem: you have SPF, but it only covers your main mail provider and not a marketing tool or CRM you also send from, so mail from that second tool fails the check.
2. DKIM isn't signing your mail
DKIM adds a cryptographic signature to outgoing mail, proving it genuinely came from your domain and wasn't altered in transit. Unlike SPF, DKIM has no way to self-discover in DNS — providers publish it under a selector name that varies (Google uses google, Microsoft 365 uses selector1/selector2, and so on), and if that record was never actually published — or was set up once and then quietly stopped matching after a provider migration — your mail arrives unsigned, and unsigned mail is exactly what phishing looks like from the receiving end.
3. DMARC exists but isn't actually enforced
Here's the counterintuitive one: DMARC on its own doesn't stop anything. Most domains that have DMARC are set to p=none — a monitoring-only mode that collects reports but blocks nothing. That's often the right first step, not a mistake, but it also means DMARC isn't the reason your legitimate mail is failing — because at p=none, DMARC isn't making delivery decisions at all. If mail's landing in spam, the actual cause is almost always #1 or #2 above; DMARC just determines what happens to mail that fails those.
4. Your domain is on a blocklist
Even with SPF, DKIM, and DMARC all correct, a domain can get flagged on a blocklist like Spamhaus's Domain Block List — usually from something upstream (a compromised account, a marketing send that got reported as spam by too many recipients, or a domain that was previously used for something abusive before you owned it). Once listed, many providers reject or spam-folder mail referencing that domain regardless of how clean your authentication setup is.
Check which of these is actually your problem
Paste your domain below — this checks all four, free, no signup:
We only read public DNS — never your inbox. Nothing is stored unless you explicitly ask us to email you a copy.
mail.yourdomain.com or news.yourdomain.com? Check that separately — it needs its own SPF, DKIM, and DMARC, and a clean result above doesn't cover it.If it comes back clean
These four checks don't catch everything — sender reputation, engagement rates, and content itself also affect spam placement, and none of those are things a DNS check can see. But SPF, DKIM, DMARC, and blocklisting are the specific, fixable, technical causes — and by far the most common ones, since they're also the easiest to get wrong and the easiest to forget once set up. If your setup checks out clean above and mail is still landing in spam, the cause is likely on the content or reputation side instead, not something this tool measures.
Fixed something above? It's worth re-checking after any change since providers occasionally update their sending infrastructure without telling you. Start monitoring and we'll re-check daily and email you the moment something breaks — free for 14 days, then $19/mo.