1. Error
After installing the W3 Total Cache plugin in a WordPress based website, the Settings web page for the plugin indicated a critical error. After examining the error log file the following error was observed.
PHP message: PHP Fatal error: Uncaught Error: Class "DOMDocument" not found in /wp-content/plugins/w3-total-cache/Util_Ui.php:1521
2. Solution
The reason for the error was that the PHP DOM extension, which is a part of PHP’s XML extension, was missing on the server. The problem was rectified by installing the php-xml package, using the following commands.
$ sudo apt-get update $ sudo apt-get install php8.3-xml
The web server was restarted with the command,
$ sudo systemctl restart nginx
