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Fix Microsoft 365 Email Rejected Due to SpamCop Blocklist
Question details
Users are experiencing email delivery failures in Microsoft 365 because the outbound Exchange Online IP address has been flagged on SpamCop or other real-time blocklists.
- Product
- Microsoft 365
- Device & OS
- not provided
- Scenario
- Sending outbound emails to external recipients through Exchange Online.
- Observed behavior
- Messages are rejected, and a non-delivery report (NDR) is generated stating that the Microsoft outbound IP is listed on a blocklist.
Ensure you have the complete non-delivery report (NDR) for the rejected email, as you will need to provide the recipient domain, rejection time, and listed outbound IP address to Microsoft Support.
Submit a Support Request via Microsoft 365 Admin Center
Because Microsoft controls the outbound IP pool, Global Administrators must contact Microsoft Support to investigate the IP reputation and coordinate mitigation.
Microsoft manages a shared pool of outbound IP addresses for Exchange Online. When one of these IPs is blacklisted by SpamCop, individual tenant admins cannot delist it directly. Microsoft's engineering team must intervene.
Open your web browser and sign in to the Microsoft 365 admin center using your Global Administrator credentials.
Navigate to the bottom right corner of the dashboard and select the 'Help & support' option.
Choose 'Contact support' and provide a brief description of the blocklist issue in the text field.
Attach the complete non-delivery report (NDR) and manually include the recipient domain, the exact rejection time, and the listed outbound IP address in the ticket details.
Submit the support request so the Microsoft team can investigate the reputation of the outbound IP and coordinate delisting with SpamCop.
Escalate to Your IT Administrator (For End Users)
End users cannot resolve outbound IP blocklist issues directly and must escalate the problem to their internal IT team.
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- 1. Visit the Website: Go to the official WPS Office website to find the appropriate download version for your system.
- 2. Download the Installer: Click the 'Free Download' button to save the installation package to your computer.
- 3. Install and Run: Launch the installer, follow the on-screen instructions, and open WPS Office to start working on your documents immediately.
Frequently Asked Questions
Why is a Microsoft 365 IP address listed on SpamCop?
Microsoft 365 uses a shared pool of outbound IP addresses. If a compromised tenant sends spam through these IPs, services like SpamCop may temporarily block the IP, affecting other legitimate users sharing that same address.
Can I remove the Microsoft IP from SpamCop myself?
No, you cannot delist the IP yourself. Because Microsoft owns and controls the outbound IP pool, only Microsoft Support can investigate the root cause, block the spamming tenant, and request delisting from SpamCop.
What information is required to open the support ticket?
You need to provide the complete non-delivery report (NDR) as an attachment, the recipient's domain name, the exact time the email was rejected, and the specific outbound IP address mentioned in the bounce message.
Are there temporary workarounds while waiting for Microsoft to delist the IP?
In some environments, admins can route outbound mail through a third-party smart host or email security gateway to bypass Microsoft's native outbound IP pool until the blocklist issue is resolved.
