Spam filter / gateway
FireEye SMTP Error Codes and Rejection Messages
FireEye, now part of Trellix, is a mail security gateway that filters mail through its own servers before delivery, with recipient-managed allowlists and policy controls.
- Codes on record
- 1
- Responses
- 1
SMTP 5501 response
A hard failure. The receiving server has refused the message for good and will not accept an unchanged retry without a change on the sending side. See SMTP 550 across every provider
FireEye bounce questions
›Why is FireEye bouncing my email?
FireEye, now part of Trellix, is a mail security gateway that filters mail through its own servers before delivery, with recipient-managed allowlists and policy controls. Match the exact wording of your bounce to one of the 1 responses on this page to find the specific reason and fix.
›How do I get past the FireEye spam filter?
Authenticate with SPF, DKIM and DMARC, keep your sending IP and domain reputation clean, mail only engaged recipients, and honour unsubscribes.
