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Resolving Common WP Fastest Cache Issues: A Troubleshooting Guide

50 threads Sep 9, 2025 Plugin → Wp fastest cache

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WP Fastest Cache is a powerful tool for speeding up your WordPress site, but like any complex plugin, it can sometimes interact unexpectedly with your theme, other plugins, or server configuration. Based on common issues reported by users, this guide outlines the most frequent problems and their potential solutions.

1. Cached Pages Ignoring Security or Access Rules

The Problem: Security plugins like NinjaFirewall or Wordfence that block requests at the server level (via auto_prepend_file) may find their blocks are bypassed. The cache serves a saved HTML file, showing a seemingly successful page load even when an attack or unauthorized access should have been blocked with a 403 error.

Why It Happens: This typically occurs when WP Fastest Cache is configured to use mod_rewrite rules in the .htaccess file. In this mode, the server serves the cached .html file before the PHP application (and its security layers) can even process the request.

Potential Solutions:

  • Test Compatibility: The first step is to verify if the security plugin is compatible with caching. Contact the support teams for both plugins to confirm.
  • Exclude Sensitive Pages: A common workaround is to exclude any login, admin, or security-check pages from being cached within the WP Fastest Cache settings.
  • Consider PHP Caching: If possible, switch the cache delivery method to PHP within WP Fastest Cache's settings, though this may have performance implications.

2. CSS, Fonts, or JavaScript Not Loading Correctly

The Problem: After enabling the cache, your site's styling may break. Fonts don't load, featured images in APIs disappear, or pages look unstyled. This is often linked to the plugin's optimization features, not the core caching system.

Why It Happens: The "Combine CSS" or "Minify" options can sometimes process files in an order that breaks dependencies or incorrectly handles resources like base64-encoded fonts.

Potential Solutions:

  • Disable Optimization Options: As a first step, go to WP Fastest Cache settings and disable all optimization checkboxes (e.g., Combine CSS, Minify CSS/JS). Only leave the "Cache System" option enabled.
  • Clear Cache: After changing these settings, clear all cache again to regenerate the files without the problematic optimizations.
  • Re-enable Options One-by-One: To identify the exact culprit, re-enable the optimization options one at a time, clearing the cache each time, until the problem reappears.

3. Cache Not Working or Updating Properly

The Problem: The cache doesn't seem to create files, doesn't update after you publish new content, or the diagnostic comment () is missing from your page source.

Why It Happens: This can be caused by conflicts with other plugins, incorrect file permissions on the server, or a server-side caching system (like Varnish or Object Cache) that is serving content before WP Fastest Cache can.

Potential Solutions:

  • Check for Plugin Conflicts: Temporarily disable all other plugins to see if the cache starts working. If it does, reactivate them one by one to find the conflict.
  • Confirm Server Compatibility: Ensure your hosting environment supports .htaccess mod_rewrite rules if you are using that mode. Check with your host about any server-level caching.
  • Reinstall the Plugin: A simple but often effective fix is to completely delete and reinstall the WP Fastest Cache plugin.

4. Issues with Dynamic Content (Logins, Embeds, Affiliate Links)

The Problem: Cached pages break functionality that requires PHP to run, such as redirecting after login, displaying geo-targeted affiliate links correctly, or fully rendering embedded content from your own site.

Why It Happens: A cached page is a static HTML file. Any dynamic process that requires real-time PHP execution will not work on that cached page.

Potential Solutions:

  • Exclude Pages: The most reliable method is to exclude the specific pages that need to be dynamic (e.g., /wp-admin/, /login/, pages with affiliate links) from being cached.
  • Check for Compatibility: For features like geo-targeting, confirm that the other plugin is designed to work with caching systems. It may need to use JavaScript for redirection instead of server-side PHP.

General Troubleshooting Steps

If you encounter an issue not listed above, always start with these basic steps:

  1. Clear All Cache: Clear the cache within WP Fastest Cache and any other caching layers (e.g., Cloudflare, server cache).
  2. Disable Other Plugins: Rule out conflicts by disabling all other plugins except WP Fastest Cache.
  3. Use a Default Theme: Temporarily switch to a default WordPress theme (like Twenty Twenty-Four) to rule out a theme conflict.
  4. Check .htaccess: Ensure your .htaccess file is writable and the WP Fastest Cache rules are present.

Remember, the WP Fastest Cache team frequently releases updates to address bugs and improve compatibility. Always ensure you are using the latest version of the plugin.

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