What does “policy reasons” mean in Yahoo bounce messages?

Yahoo's "policy reasons" bounce messages indicate rejection based on sending behavior or content rather than technical failures. These rejections typically use 5xx error codes with vague descriptions that do not specify the exact policy violated.

Common causes include excessive complaint rates, authentication failures, content triggering spam filters, sending from blocklisted IPs, or volume patterns that appear abusive. Yahoo intentionally keeps these messages vague to prevent spammers from gaming the system.

Resolving policy rejections requires systematic investigation. Review authentication setup, check IP and domain reputation through available tools, examine recent sending patterns, and analyze content for potential triggers. If problems persist, Yahoo offers a sender support form for legitimate senders to request review, though response times vary.