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How to Fix the 'Scan Stage Failed' Error in Wordfence Security

25 threads Sep 7, 2025 Plugin → Wordfence security

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If you're seeing the "Scan Stage Failed" error in your Wordfence Security plugin, you're not alone. This is a common issue that prevents the security scanner from completing its work, leaving your site potentially unprotected. This guide will explain why this error occurs and walk you through the most effective troubleshooting steps to resolve it.

What Does the "Scan Stage Failed" Error Mean?

The error message states: "A scan stage has failed to start. This is often because the site either cannot make outbound requests or is blocked from connecting to itself." In simple terms, the Wordfence scan process, which runs in stages, is unable to initiate one of those stages. This is typically caused by a connectivity problem where your WordPress site cannot send a request to itself (a "loopback" request) to start the next part of the scan.

Common Causes of the Scan Failure

Based on community reports, the scan failure is usually triggered by one of the following:

  • Server Firewalls or Security Rules: Your web server or hosting provider's firewall may be blocking the internal connections Wordfence needs to make.
  • Third-Party Firewalls & Plugins: Other security plugins, especially those that block countries or IPs (like IQ Block Country), can inadvertently block Wordfence's servers or your own site's IP address.
  • Cloudflare or CDN Settings: Misconfigured Cloudflare rules or other Content Delivery Networks can return "403 Forbidden" or "503 Service Unavailable" errors to loopback requests.
  • Caching Issues: Object caching or persistent page caching can sometimes interfere with the scan initiation process.
  • IPv6 Misconfiguration: If your server does not fully support IPv6, it can cause connection failures.
  • Resource Limitations: A low maximum execution time on the server can cause the scan process to time out before a stage can begin.

Step-by-Step Troubleshooting Guide

Try these solutions in order. After each step, attempt to run a new scan to see if the issue is resolved.

Step 1: Adjust Scan Performance Settings

This is the most common first step recommended in the community.

  1. In your WordPress dashboard, go to Wordfence > Scan.
  2. If a scan is running, click the Stop New Scan button.
  3. Navigate to Scan Options and Scheduling (or Manage Scan).
  4. Locate the Performance Options section.
  5. Set the "Maximum execution time for each scan stage" to 20.
  6. Click Save Changes.

Step 2: Enable Debugging and Review Diagnostics

Gathering more information is crucial for diagnosing stubborn problems.

  1. Go to Wordfence > Tools > Diagnostics.
  2. Scroll down to the Debugging Options section.
  3. Check the option to "Enable debugging mode".
  4. If the option "Start scan remotely" is checked, uncheck it.
  5. Click Save Changes.
  6. Now, run a new scan. After it fails, return to the Diagnostics page. You will find a new "Scan Log" section that provides detailed timestamps and error messages. This log is invaluable for pinpointing the exact failure point.

Step 3: Check for Conflicts with Other Plugins

  1. Temporarily disable all other plugins besides Wordfence.
  2. Try running a Wordfence scan. If it works, you know another plugin is causing the conflict.
  3. Re-enable your plugins one by one, running a scan after each, to identify the culprit. Pay special attention to security, firewall, and caching plugins.
  4. For firewall/blocking plugins, you may need to whitelist the IP addresses used by Wordfence. A list of these IPs can be found on the Wordfence help site.

Step 4: Clear All Caches

If you use a caching plugin or your host employs server-level caching, clear all possible caches, including:

  • Page Cache
  • Object Cache (e.g., Redis, Memcached)
  • CDN Cache (e.g., Cloudflare)

Step 5: Investigate Server Connectivity Issues

The Diagnostics page provides key clues. Look for these tests:

  • Connecting back to this site: If this test fails with a 403 Forbidden or 503 Service Unavailable error, it confirms your site is blocking its own connections.
    • If you use Cloudflare, you may need to adjust firewall rules or pause Cloudflare temporarily to test. The error often explicitly mentions Cloudflare.
    • Contact your hosting provider and ask them to check their firewall or mod_security rules for any blocks on loopback connections (your site making requests to itself).
  • IPv6 DNS resolution: If this test fails, force Wordfence to use IPv4. Go to Scan > Scan Options and Scheduling > Advanced Scan Options and enable "Use only IPv4 to start scans". Save changes and try again.

Step 6: When All Else Fails – Send Diagnostics

If you have tried all the steps above and the scan still fails, the problem may require deeper investigation. You can export your diagnostic information for further analysis.

  1. Go to Wordfence > Tools > Diagnostics.
  2. At the top of the page, click the link to "Send Report by Email" or use the "Export" button to download a copy.

Conclusion

The "Scan Stage Failed" error is almost always a connectivity issue. By methodically working through these troubleshooting steps—adjusting performance settings, checking for plugin conflicts, clearing caches, and investigating server firewall rules—you can usually identify and resolve the underlying cause, allowing Wordfence Security to protect your site effectively once again.

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