Установка из официального репозитория:

wget https://repo.zabbix.com/zabbix/4.4/ubuntu/pool/main/z/zabbix-release/zabbix-release_4.4-1%2Bbionic_all.deb
sudo dpkg -i zabbix-release_4.4-1+bionic_all.deb
sudo apt update
sudo apt-get install zabbix-agent
sudo nano /etc/zabbix/zabbix_agentd.conf
	Server=192.168.205.55
	ServerActive=192.168.205.55
	Hostname=mi-*******
sudo service zabbix-agent restart
sudo systemctl enable zabbix-agent