How to fix WordPress 404 errors calling theme assets.

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What do you do when you have fifteen “404” errors reported by WebPagetest.org. This is bad news and causes erratic delays in page loading.

Looking at the image below all of the red lines are 404 errors. Our guess is it’s causing about a one-second loading error on this site. The server is missing Javascript assets from plugins. But we see all sort of things missing during tests – especially small PNG files. Those need to be tracked down and replaced.

Sometimes a potential, simple 404 fix might be reinstalling your theme – or else isolating the missing files from the theme package and uploading them individually to the right server folders via Cpanel or FTP.

We’ve also seen site owners place “dummy” assets (empty files) for the theme to call. This reduces the errors. We’ve done this trick, too, even though it is not a good practice. It sort of fixes the problem.

Speed test results showing red 404 errors.
Speed test results showing red 404 errors. Click to enlarge.

Do you have missing assets causing 404 errors and speed delays?

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by - Brad Teare