PidFile=/var/run/zabbix/zabbix_agent2.pid
LogFile=/var/log/zabbix/zabbix_agent2.log
LogFileSize=100
DebugLevel=4
EnableRemoteCommands=1
LogRemoteCommands=0
Server=127.0.0.1
ListenPort=10050
ServerActive=127.0.0.1
Hostname=host
RefreshActiveChecks=120
BufferSend=5
BufferSize=100
MaxLinesPerSecond=100
Timeout=3
Include=/etc/zabbix/zabbix_agentd2.d
UnsafeUserParameters=0
ControlSocket=/tmp/agent.sock

...
2019/10/24 12:35:43.169203 received passive check request: 'system.run[systemctl list-unit-files]' from '127.0.0.1'
2019/10/24 12:35:43.169272 [0] processing update request (1 requests)
2019/10/24 12:35:43.169302 [0] adding new request for key: 'system.run[systemctl list-unit-files]'
2019/10/24 12:35:43.169314 [0] created direct exporter task for plugin 'SystemRun' itemid:0 key 'system.run[systemctl list-unit-files]'
2019/10/24 12:35:43.169356 executing direct exporter task for key 'system.run[systemctl list-unit-files]'
2019/10/24 12:35:43.169370 failed to execute direct exporter task for key 'system.run[systemctl list-unit-files]' error: 'Remote commands are not enabled.'
...

~$ cat /etc/debian_version
9.11
:~$ apt-cache policy zabbix-agent2
zabbix-agent2:
 Installed: 1:4.4.0-1+stretch
 Candidate: 1:4.4.0-1+stretch
 Version table:
 *** 1:4.4.0-1+stretch 500
 500 http://repo.zabbix.com/zabbix/4.4/debian stretch/main amd64 Packages
 100 /var/lib/dpkg/status