Error : 550 mail from your IP refused by ZapBL in Email Security.cloud

Products

• Email Security.cloud

Issue/Introduction

Track and Trace logs show the error: 550 mail from your IP refused by ZapBL, see http://www.zapbl.net
The delivery fails for specific outbound IP addresses.

Environment

Email Security.cloud

Cause

The recipient's network uses ZapBL, a third-party blocklist, which has flagged a specific Broadcom outbound IP address. This is an independent service not managed by Broadcom.

Resolution

Since ZapBL is a third-party service, use the following steps to ensure delivery:

• Recipient Whitelisting: Request the recipient's IT team to add the Broadcom/Symantec IP ranges to their "Allow" or "Whitelist" to bypass third-party blocklist checks.
• IP Ranges: Provide the recipient with the official IP ranges: IP address ranges for Email Security.cloud.
• Retry Delivery: Resend the email. Email Security.cloud uses multiple delivery IPs; a subsequent attempt may use an IP that is not blacklisted.