you can try...here
[root@email roundcubemail-0.7]# pwd
/var/www/roundcubemail-0.7
[root@email roundcubemail-0.7]# cd plugins/password/
config.inc.php drivers/ package.xml password.php
config.inc.php.dist localization/ password.js README
[root@email roundcubemail-0.7]# cd plugins/password/
[root@email password]#
[root@email password]# vim config.inc.php
#$rcmail_config['password_db_dsn'] = "mysqli://roundcube:Kwnw3mjWrWWjI6O5qsOmHI0pI6n8hW@127.0.0.1/vmail";
Change this line to look like this 👇
$rcmail_config['password_db_dsn'] = "mysql://root:root@127.0.0.1/vmail";
Where root:root means: your account: your password.