N.B.: All commands are supposed to be run by root. If you are logged in as a regular user with sudo rights, please prepend ___sudo___ to each of the commands.
During the installation you'll be asked to enter the hostname of the Jitsi Meet instance. If you have a FQDN hostname for the instance already set ip in DNS, enter it there. If you don't have a resolvable hostname, you can enter the IP address of the machine (if it is static or doesn't change).
This hostname (or IP address) will be used for virtualhost configuration inside the Jitsi Meet and also you and your correspondents will be using it to access the web conferences.
Launch again a browser with the Jitsi Meet URL and you'll see a telephone icon on the right end of the toolbar. Use it to invite SIP accounts to join the current conference.
When this happens, just run the deinstall command a second time and it should be ok.
The reason for failure is that not allways the daemons are stopped right away, there is a timeout before the actual stop. And if the unistall script goes on before the services' stop, there is an error.
The second run of the deinstall command fixes this, as by then the jigasi or jvb daemons are already stopped.