Level: Advanced
A systematic technical diagnosis, rather than guessing, is the fastest path to resolving an unexplained spam placement problem.
Start by Confirming Authentication Is Actually Passing
Checking the full authentication results on a real delivered message rules out or confirms SPF, DKIM, and DMARC as the cause before investigating anything else.
Check Reputation and Blocklist Status Next
If authentication is confirmed passing, checking whether the sending IP or domain has recently been added to any blocklists, or shows degraded reputation, is the next logical step.
Isolate Whether It's Provider-Specific or Universal
Determining whether the spam placement is happening across all recipient providers or concentrated at one specific provider significantly narrows down the likely cause and appropriate fix.
Next step: Use the Blacklist Lookup to check your sending domain and IP against current blocklists as an early step in diagnosing unexplained spam placement.