Your requirements could not be resolved to an installable set of packages. Problem 1 - phpunit/phpunit[4.8.36, 5.5.0, ..., 5.7.27, 6.5.0, ..., 6.5.14, 7.5.0, ..., 7.5.20, 9.0.0, ..., 9.6.17] require ext-dom * -> it is missing from your system. Install or enable PHP's dom extension. - Root composer.json requires phpunit/phpunit ^4.8.36 || ^5.5 || ^6.5 || ^7.5 || ^9.0 -> satisfiable by phpunit/phpunit[4.8.36, 5.5.0, ..., 5.7.27, 6.5.0, ..., 6.5.14, 7.5.0, ..., 7.5.20, 9.0.0, ..., 9.6.17]. To enable extensions, verify that they are enabled in your .ini files: - /etc/php/7.4/cli/php.ini - /etc/php/7.4/cli/conf.d/20-json.ini - /etc/php/7.4/cli/conf.d/20-mbstring.ini - /etc/php/7.4/cli/conf.d/20-phar.ini - /etc/php/7.4/cli/conf.d/99-pecl.ini You can also run `php --ini` in a terminal to see which files are used by PHP in CLI mode. Alternatively, you can run Composer with `--ignore-platform-req=ext-dom` to temporarily ignore these required extensions.