Some Emails Rejected Due to a Banned Quest IP Address – How to Submit a Delisting Request (4379289)

An organization using Domain Rewrite with Quest On Demand Migration (ODM) reported that certain emails were being rejected by Microsoft 365. Investigation revealed that the source IP address used to send these emails was blocked, preventing delivery to Office 365 recipients.

Microsoft flagged the Quest IP address as potentially abusive or malicious, triggering Office 365’s anti-spam protection mechanisms. As a result, emails sent using this IP were automatically rejected.

To resolve the issue, the sender must request delisting of the affected IP via Microsoft's delisting portal. Even though the IP is owned by Quest, Microsoft requires that the sender (the SMTP email address used in the rejected message) initiate and verify the delisting request.

Steps to Delist the IP Address

1. Visit the Office 365 Anti-Spam IP Delist Portal at:
   https://sender.office.com

2. On Step 1, provide:

   • The email address used to send the rejected message.

   • The IP address that appears in the rejection error (e.g., 20.230.234.206).

   • The CAPTCHA characters shown on screen.

    

3. A verification email will be sent to the provided sender address.

4. Once the sender confirms their identity via the verification email, the system will proceed to delist the IP.

Note: Only the original sender can verify and complete the delisting process. Quest Support cannot do this on behalf of the customer.