http 500 errors

[Mta]

* Upgrade Plesk Obsidian
- webmail.xxxxxx.net http 500 errors

PHP Fatal error:  Uncaught Error: Class 'PDO' not found in /usr/share/psa-roundcube/program/lib/Roundcube/rcube_db_mysql.php:144

[SKaero]

Roundcube requeres the php PDO extension, it looks like you've missing it https://www.php.net/manual/en/pdo.installation.php