Fatal error on activation

After installing the plugin on WordPress 6.1.1, PHP 7.4.3, Ubuntu 20, when I try to Activate I get the error below: Fatal error: Uncaught Error: Call to undefined function Puvox\mb_ereg_replace() in /var/www/mysite/wp-content/plugins/wp-phpmyadmin-extension/library.php:281 Stack trace: #0 /var/www/mysite/wp-content/plugins/wp-phpmyadmin-extension/index.php(698): Puvox\library::realpath() #1 /var/www/mysite/wp-content/plugins/wp-phpmyadmin-extension/index.php(94): WpPhpMyAdminExtension\PluginClass->file_put_contents() #2 /var/www/mysite/wp-includes/class-wp-hook.php(308): WpPhpMyAdminExtension\PluginClass->setup_definitions() #3 /var/www/mysite/wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters() #4 /var/www/mysite/wp-includes/plugin.php(517): WP_Hook->do_action() #5 /var/www/mysite/wp-admin/admin.php(175): do_action() #6 /var/www/mysite/wp-admin/index.php(10): require_once('/var/www/barnes…') #7 {main} thrown in /var/www/mysite/wp-content/plugins/wp-phpmyadmin-extension/library.php on line 281 A search here has shown this reported before, and the fix suggested was to make sure the ‘mbstring’ extension was enabled. But I have installed and enabled it, as far as I can tell. php -r "print_r(get_loaded_extensions());" shows ‘mbstring’ as one of the loaded extensions. What else might be wrong? If it’s significant, we have a live site and a staging site and on the live site the plugin version is 5.2.0.7 and all seems to be OK. The problem only exists on the staging site (otherwise identical) where the plugin was updated to 5.2.1.02. LATER: Having reverted to 5.2.0.7, the problem has gone away. So there may be some new issue there. This reply was modified 3 years, 2 months ago by johnny2r .