Hello,

i think it is a bug because the zabbix agent has both parameters set for systemd.

Steps to reproduce:

1. When i use the orginal config under /usr/lib/systemd/system/zabbix-server.service
   the service doesn't start
2. When i add in the Service config under /usr/lib/systemd/system/zabbix-server.servie
   User and Group  "zabbix" the Server Starts

Result:

STATUS Output:
zabbix-server.service - Zabbix Server
Loaded: loaded (/usr/lib/systemd/system/zabbix-server.service; enabled; vendor preset: disabled)
Active: activating (auto-restart) (Result: exit-code) since Thu 2020-05-28 16:54:44 CEST; 2s ago
Process: 7202 ExecStart=/usr/sbin/zabbix_server -c $CONFFILE (code=exited, status=1/FAILURE)
Main PID: 6919 (code=exited, status=0/SUCCESS)

Messages LOG:

May 28 16:55:15 testserver zabbix_server[7211]: zabbix_server [7211]: Cannot initialize IPC services: Cannot access path "/var/run/zabbix": [13] Permission denied.
May 28 16:55:15 testserver systemd[1]: zabbix-server.service: Control process exited, code=exited status=1
May 28 16:55:15 testserver systemd[1]: zabbix-server.service: Failed with result 'exit-code'.
May 28 16:55:15 testserver systemd[1]: Failed to start Zabbix Server.
May 28 16:55:25 testserver systemd[1]: zabbix-server.service: Service RestartSec=10s expired, scheduling restart.
May 28 16:55:25 testserver systemd[1]: zabbix-server.service: Scheduled restart job, restart counter is at 98.
May 28 16:55:25 testserver systemd[1]: Stopped Zabbix Server.
May 28 16:55:25 testserver systemd[1]: Starting Zabbix Server...
May 28 16:55:25 testserver zabbix_server[7213]: zabbix_server [7213]: Cannot initialize IPC services: Cannot access path "/var/run/zabbix": [13] Permission denied.
May 28 16:55:25 testserver systemd[1]: zabbix-server.service: Control process exited, code=exited status=1
May 28 16:55:25 testserver systemd[1]: zabbix-server.service: Failed with result 'exit-code'.
May 28 16:55:25 testserver systemd[1]: Failed to start Zabbix Server.

[root@testserver zabbix]# ls -l /var/run/ | grep zabbix
drwxr-xr-x. 2 zabbix zabbix 120 May 28 16:38 zabbix

########

[Unit]
Description=Zabbix Server
After=syslog.target
After=network.target
After=mysql.service
After=mysqld.service
After=mariadb.service
After=postgresql.service

[Service]
Environment="CONFFILE=/etc/zabbix/zabbix_server.conf"
EnvironmentFile=-/etc/sysconfig/zabbix-server
Type=forking
Restart=on-failure
PIDFile=/run/zabbix/zabbix_server.pid
KillMode=control-group
ExecStart=/usr/sbin/zabbix_server -c $CONFFILE
ExecStop=/bin/kill -SIGTERM $MAINPID
RestartSec=10s
TimeoutSec=0
User=zabbix
Group=zabbix

[Install]
WantedBy=multi-user.target