Master the trifecta of modern email authentication: DKIM 2048-bit cryptographic signatures, strict SPF syntax, and DMARC p=reject enforcement.
Why Emails Land in Spam: The Authentication Problem
Major mailbox providers (Google Workspace, Gmail, Microsoft 365, Yahoo) enforce mandatory authentication requirements. Any outgoing message lacking aligned SPF, 2048-bit DKIM signatures, and a valid DMARC policy is rejected or filtered into spam.