resolve some issues on ISPConfig 3.2.2 with Linux Debian 9

We are searching a skilled person on ISPCONFIG , please do not propose Yourself if You aren'.t. These are the problems to solve in a production server with Linux Debian 9 , ISPConfig 3.2.2, Apache 2.4 , PHP 7.4 and let's Encrypt: - vhosts are online but main site (ispconfig host) is not reachable and uses the self signed certificate instead of let's encrypt; - postscript and dovecot are working but use the self signed certificate instead of let's encrypt; - one email account of a customer is not accessible due misconfiguration; - ispconfig and phpmyadmin is not reachable; - fail2ban is not active and activating the firewall makes the system inaccessible; The system uses custom configurations for vhosts to use http2 and brotli, they must be preserved. We estimate that the works can be done in 2/3 hours . There are additional maintenance tasks to be done in the future .