Roundcube: How do decrease response time to failed login attempts?
I found this hack: https://github.com/roundcube/roundcubemail/issues/7754
Change line 163 of the rcube_imap.php file in Debian distribution of rc in /var/lib/roundcube/program/lib/Roundcube to:
} while(!$this->conn->connected() && $data['retry']);