FAQ: Debugging

I've been using the plugin for some time, I updated one of my other plugins and now it doesn't work anymore. What's up?

It's likely the plugin author modified their JS or CSS in the new release and any old CSS or JS you optimized with our plugin has introduced duplicate code as a result (creating a conflict). Simply check out the source code, identify any new CSS or JS and update your CSS and JS optimizations our plugin and you're good to go.

I see garbage characters instead of the normal web site, what's going on here?

If a theme or it's files use the call php_flush() or function flush() that will interfere with the plugins normal operation; making the plugin send cached files before essential operations have finished. The flush() call is no longer necessary and should be removed.

I'm getting blank pages or 500 error codes when trying to upgrade on WordPress MU

First, make sure the plugin is not active (disabled) network-wide. Then make sure it's deactivated network-wide. Now you should be able to successful upgrade without breaking your site.

When I post / like my posts on Facebook the wrong text or no images are shown on Facebook.

If this happens you need to add the following user agents to the textarea "Rejected user agents" the Page Cache settings page:

facebookexternalhit
FacebookExternalHit/1.1
FacebookExternalHit/1.0

Also make sure you have the correct xmlns:og /xmlns:fb tags in your opening HTML tag.

Why doesn't minify work for me?

Great question. W3 Total Cache uses several open source tools to attempt to combine and optimize CSS, JavaScript and HTML etc. Unfortunately some trial and error is required on the part of developers is required to make sure that their code can be successfully minified with the various libraries W3 Total Cache supports. Even still, if developers do test their code thoroughly, they cannot be sure that interoperability with other code your site may have. This fault does not lie with any single party here, because there are thousands of plugins and theme combinations that a given site can have, there are millions of possible combinations of CSS, JavaScript etc.

A good rule of thumb is to try auto mode, work with a developer to identify the code that is not compatible and start with combine only mode (the safest optimization) and increase the optimization to the point just before functionality (JavaScript) or user interface / layout (CSS) breaks in your site.

We're always working to make this more simple and straight forward in future releases, but this is not an undertaking we can realize on our own. When you find a plugin, theme or file that is not compatible with minification reach out to the developer and ask them either to provide a minified version with their distribution or otherwise make sure their code is minification-friendly.

A notification about file owner appears along with a FTP form, how can I resolve this?

The plugin uses WordPress FileSystem functionality to write to files. It verifies that file owner, file owner group of created files match process owner. If this is not the case it cannot write or modify files.

Typically, you should ask your web host about the permissions issue and they should be able to resolve it.

You can however try adding define('FS_METHOD', 'direct'); to wp-config.php to circumvent the file and folder checks.

I get an CloudFlare error message similar too "certificate verify locations: CAfile: /etc/path/certs/ca-bundle.crt CApath: none"

This is happens when CURL cannot find the proper location of certificates or the certificates have incorrect permissions. Ask your web host for help addressing this issue.