When I arrived to the step "Configure the package manager"
The following message is displayed :
"
The installer failed to download the public key used to sign the local repository at http://repo.zabbix.com/zabbix/3.2/ubuntu:

http://repo.zabbix.com/RPM-GPG-KEY-ZABBIX-A14FE591
...
Downloading local repository key failed:
"
At the end all the packages are not downloaded which is a problem and Zabbix Appliance is not properly configured ...