Check your version: zabbix_server -V . If older than 5.0 LTS, plan an upgrade. If the error persists and you are certain configs are correct, manually clear stale IPC resources.
[Service] LimitNOFILE=65536 LimitNPROC=65536 Reload: systemctl daemon-reload && systemctl restart zabbix-server . Older Zabbix versions (3.x, 4.x) had known bugs in IPC handling under load, especially with the upd (update) process. Zabbix 6.2+ and 7.0+ have substantially improved IPC resilience. zabbix cannot write to ipc socket broken pipe upd
Edit /etc/security/limits.conf :
Stop Zabbix server first.
Edit /etc/zabbix/zabbix_server.conf :