On WordPress sites a common error message is “There has been a critical error on this website. Please check your site admin email inbox for instructions”. It can appear on the front of the site and when you try to log in to the WordPress dashboard.
This is almost always a PHP compatibility issue or code error, where a plugin or theme throws an error and the site cannot be loaded. Usually the plugin is not compatible with the site’s PHP version, or it conflicts with another plugin.
The video below walks through how to troubleshoot and solve this on WP Alpha hosting. A similar approach works on any other hosting. Broadly, you check the error log on the server, trace the plugin causing the issue and disable it. In the video, the SeedProd Coming Soon Page plugin was the root cause: it was nearly 3 years out of date and not compatible with PHP 8.0.
Step by step
- Log in to the hosting admin console and open File Manager.
- Click Logs, then open the error log.
- Scroll right to the bottom. The newest entries are at the end. Older entries, such as certificate errors from when the site was first set up, are usually unrelated.
- Find the most recent “PHP Fatal error” message. It is technical, but it usually includes the plugin’s folder name, which tells you which plugin is causing the problem.
- Open the WordPress manager from the WordPress section, click Plugins and switch off the plugin named in the log. If that does not work, you can also deal with the plugin through File Manager.
- Reload the page that showed the error. Give it a little time: in the video the error still showed on the first reload, then the site loaded normally a short while later.
- If the error persists, reopen the error log, scroll to the bottom and check the newest lines for another plugin.
Turn on the WordPress debug log for more detail
If the error log does not point to a clear culprit, open the debugging settings in the WordPress manager. Turn on WP_DEBUG and WP_DEBUG_LOG so errors are saved to a log file, but leave the option to display errors switched off so visitors do not see them. WordPress then writes errors to httpdocs/wp-content/debug.log, which you can open in File Manager. It lists errors relating to plugins, themes and code. Switch debugging off again once the problem is fixed.
Common causes
- A plugin that is not compatible with the PHP version your site runs on, often because it has not been updated in a long time.
- Two plugins conflicting with each other.
- A code error in a plugin or theme.
If you get stuck, our support team can help. Log a ticket from the client area or start a live chat.