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Why Broken Link Checker Shows False Positives and How to Fix It

27 threads Sep 16, 2025 Plugin → Broken link checker

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If you've found your way here, you're likely frustrated by your Broken Link Checker plugin flagging perfectly good links as broken. You're not alone. This is one of the most common issues reported by users of the plugin. This guide will walk you through the primary reasons for these false alarms and the most effective steps you can take to resolve them.

What Are False Positives?

A false positive occurs when the Broken Link Checker plugin incorrectly reports a healthy, working link as broken. Users commonly see errors like "server not found," HTTP code "0," "403 Forbidden," or "500 Internal Server Error" for links that load perfectly in a web browser.

Why Does This Happen?

Based on extensive community reports, false positives are rarely due to an actual broken link. Instead, they are typically caused by one of the following factors:

  • Server Blocking: The single most common cause. Many websites, including major platforms like Bloomberg, Twitter/X, and Instagram, employ firewalls and security measures that block automated requests from tools like Broken Link Checker. The plugin's request might be identified as a bot and rejected, while a normal visit from your browser is allowed.
  • cURL Timeouts: If a target server is slow to respond, the plugin's connection attempt might time out before a response is received, resulting in an HTTP code "0" or "server not found" error.
  • Strict Security Configurations: Security plugins on your own WordPress site or strict server-level firewalls at your web host might be interfering with the plugin's ability to check links externally.
  • Redirects and Complex Links: The plugin can sometimes struggle with links that involve complex redirects, URL parameters, or dynamically generated content, misinterpreting the final result.

How to Troubleshoot and Fix False Positives

Here are the most effective solutions, compiled from successful community support threads.

1. Whitelist the Plugin's User Agent and IP

This is often the most critical step. If your security plugin or hosting firewall is blocking outgoing requests, it will cause false positives. You need to tell your security tools to allow requests from the Broken Link Checker.

  • Find the official User Agent and IP address ranges for the plugin (this information can typically be found in the plugin's documentation or by contacting your hosting provider).
  • Add these details to the allowlist/whitelist of any security plugin you use (e.g., Wordfence, Sucuri).
  • Contact your hosting support and ask them to ensure these details are not being blocked at the server level.

2. Adjust Server Timeout Settings

If you see HTTP code "0" or frequent timeouts, your server might be killing the connection too quickly.

  • Increase the max_execution_time and max_connection_time in your server's PHP configuration. Your hosting provider can often help with this.

3. Manually Mark Links as "Not Broken"

For links that are consistently flagged incorrectly, you can manually tell the plugin to ignore them.

  • In the Broken Links report, find the link and from the dropdown menu, select Not broken. This will mark it as a false positive.
  • Be aware that, as noted by users, there is currently no built-in way to automatically re-check links marked as false positives, so use this for links you are confident will remain stable.

4. Perform a Conflict Test

A theme or plugin conflict could be causing the malfunction.

  • Temporarily switch to a default WordPress theme (like Twenty Twenty-Four).
  • Deactivate all other plugins except Broken Link Checker.
  • See if the false positives stop. If they do, reactivate your themes and plugins one by one to identify the culprit.

5. Enable Debug Logging

To gather more information, enable WordPress debug logging. This might reveal underlying PHP errors that explain the faulty behavior.

  • Edit your wp-config.php file and set WP_DEBUG to true and WP_DEBUG_LOG to true.
  • Reproduce the issue and then check the wp-content/debug.log file for any relevant errors.

When All Else Fails

If you continue to experience a flood of false positives after trying these steps, it may be due to the fundamental way the plugin interacts with increasingly security-conscious websites. The Broken Link Checker team has indicated that a completely revamped version is in development, which will hopefully address these core issues.

In the meantime, these troubleshooting steps should help you significantly reduce the number of incorrect reports and make the plugin usable again.

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