The 503 Service Unavailable error can occur when you try to access your WordPress website. I noticed the error when trying to access my WordPress blog hosted on Linode and managed by Server Pilot.

This error usually occurs due to PHP processes crashing while executing a script. As a result, Apache is not getting a valid response from PHP and considers the PHP-FPM service to be unavailable.

So, how to fix this error? The most common reason for this error is a faulty WordPress plugin. Disable the plugin, and that should resolve the error.

You can read more about the same on the Serverpilot blog.

In this article, let me explain how I fixed 503 Service Unavailable error by disabling a few buggy plugins.

How to fix 503 Service Unavailable error in WordPress?

Since you cannot log in to your WordPress dashboard to disable the plugin, you need to have an FTP client like File Zilla set up to be able to access your server.

Next, we need to find the faulty plugin. To find the plugin you need to access the PHP error log.

The 503 Service Unavailable page usually shows where you can find the error log. Check the image below for reference.

1. Launch your FTP Client and log in to your server.

2. Next, navigate to the PHP error log path, as shown in the service error page.

3. Right-click on the websitename_php7.4.error.log file and select View/Edit. You may need to install the Notepad++ app if the log file does not open in the notepad app.

4. Once open, go through all the logs and the plugins that are listed. In my case, the plugins that were causing the issue were WP Downgrade and CF Post Format.

Make sure you note down the name of the plugins and themes that are causing the issue.

5. Next, open the Public/wp-content folder.

6. Open the Plugins folder. Locate the plugin that is causing the issue, right-click on the plugin folder, and select Rename.

7. Rename the plugin as disabled.pluginname. Do this for all the plugins in the error log.

To disable a problematic theme, open the Themes folder in Public/wp-content/themes and rename the problematic theme folder.

Once you have disabled all the plugins and themes (if any), restart PHP. You can restart PHP using the following command after you log in to your server as root.

sudo service phpX.Y-fpm-sp restart

In the above command, replace X.Y with your PHP version.

If not, you can reboot your server from your cloud server dashboard.

For Linode users, log in to your Linode account. Click on the Linodes tab. Click the Three-dots and select Reboot.

Once the reboot is complete, you can access your WordPress website without the 503 Service Unavailable error.

If you are using another hosting provider, refer to the documentation to know how to restart PHP or reboot the server.

That’s it. By following the steps in the article, you can fix the 503 Service Unavailable ‘PHP did not respond properly to the request; as a result, Apache considers the PHP-FPM service to be unavailable’ error in WordPress.