When your mail lands in spam, the first suspect is not your content, it is your authentication. Mailbox providers now check SPF, DKIM and DMARC on nearly every message, and a domain that fails them is treated as untrusted. Here are the authentication reasons your email goes to spam, and how to fix each one.
1. You have no DMARC policy
Without DMARC, receivers have no signal about how to treat mail that fails, and they lean toward caution. Publishing DMARC and advancing to enforcement is the single biggest trust improvement most domains can make. See how to set up DMARC.
2. Your SPF is broken or too permissive
An SPF record that exceeds the ten lookup limit fails with a permerror, and one that ends in +all authorizes the whole internet. Both hurt you. See how to fix SPF too many DNS lookups and how to set up SPF.
3. Your DKIM does not align
Mail signed by a platform's own domain rather than yours passes DKIM but fails DMARC alignment, which reads as unauthenticated. See how to fix DKIM alignment.
4. You are sending from a new or cold domain
Even perfect records take time to build reputation. Warm up gradually and keep volume steady rather than spiking.
5. Your sending IP is on a blocklist
If the server you send from is listed on a public blocklist, your mail is filtered regardless of authentication. A scan flags this.
Start with a scan
Most spam problems trace back to one of the first three. Scan your domain to see exactly which checks fail and get the record to fix them.
Reads public DNS only. Nothing is stored unless you save the domain to an account.