Security Policy Errors

How to Resolve False-Positive Phishing URL Blocks in Microsoft 365

Kushani Nimanthika Sep 28, 2026 869 views

Question details

The user needs to unblock legitimate application URLs that Microsoft 365 has incorrectly flagged and quarantined as phishing or high-confidence threats.

How to Resolve False-Positive Phishing URL Blocks in Microsoft 365

Product: Microsoft 365
Device & OS: not provided
Scenario: Attempting to send or access legitimate application URLs through Microsoft 365 emails or services.
Observed behavior: Legitimate URLs are being blocked and quarantined globally by Microsoft 365 security policies due to a false-positive phishing classification.

Before you start

Gather affected domains, sample email messages, message headers, and quarantine details before submitting a request to expedite the Microsoft investigation process.

Solution 1Recommended

Submit a Detailed Support Request via Admin Center

The most effective way to resolve widespread reputation-based blocking is to have Microsoft security support investigate the false positive.

URL reputation can depend on factors like sender reputation, redirects, or linked content. Since this affects multiple tenants, direct intervention from Microsoft is required.

Open the Admin Center

Access Help and Support

Navigate to the 'Help and support' section usually located in the bottom right corner or main navigation menu.

Provide Issue Details

Describe the blocking issue clearly, making sure to include affected domains, headers, quarantine details, and previous false-positive submission results.

Contact Support

Select 'Contact Support' to officially submit the ticket for investigation by the Microsoft security team.

Submit a Detailed Support Request via Admin Center

Investigation Scope: Microsoft support is the appropriate channel for investigating a widespread false-positive classification across multiple tenants.

Solution 2

Use the Tenant Allow/Block List

Use this method as a temporary workaround to unblock the URL for your specific tenant while waiting for Microsoft's global investigation.

Free Microsoft Office alternative

Looking for a Hassle-Free Office Suite? Try WPS Office

Dealing with complex administrative centers and security blocks in Microsoft 365 can be time-consuming. If you are looking for a straightforward, lightweight, and highly compatible productivity suite, WPS Office provides excellent document management without the overhead of enterprise security false positives.

Fully compatible with Microsoft Word, Excel, and PowerPoint formats (.docx, .xlsx, .pptx).Lightweight installation with a familiar, user-friendly interface.Powerful built-in PDF editing and conversion tools.Free to use for essential everyday document tasks.

microsoft office alternative - wps office

Frequently Asked Questions

Why is Microsoft 365 flagging my legitimate website as phishing?

Microsoft 365 security relies on automated reputation systems. Your URL may be flagged due to shared hosting with malicious sites, recent domain registration, suspicious redirect behaviors, or poor sender reputation.

How long does it take for Microsoft to resolve a false-positive URL block?

Resolution times vary depending on the complexity of the case. Submitting detailed evidence such as message headers and quarantine logs through the Microsoft 365 admin center usually expedites the process.

Can I prevent future false-positive blocks in Microsoft 365?

While you cannot completely control automated filters, you can minimize risks by maintaining clean email lists, using proper email authentication (SPF, DKIM, DMARC), and ensuring your application's URLs do not use deceptive redirects.

Microsoft Office Security Issues