Why does Failed to get properties: Connection timed out error occur?

Question

linux

Good afternoon.
The script that calls the zabbix agent contains the following line:
systemctl show -p MainPID elasticsearch
If zabbix-agent is run via systemd, then the command is:

zabbix_get -s 127.0.0.1 -k processpid[elasticsearch]

It will give the following error:
Failed to get properties: Connection timed out
But if you run zabbix-agent through the console:
zabbix_agentd -c /etc/zabbix/zabbix_agentd.conf
then this error is not there.
As I understand it, this error occurs if selinux is enabled. If we turn it off (setenforce 0), then everything works like a clock.
What other possible ways to solve this problem?