diff --git a/playbooks/00_install_zabbix_agent.yml b/playbooks/00_install_zabbix_agent.yml
index b84a264..fffb1cd 100644
--- a/playbooks/00_install_zabbix_agent.yml
+++ b/playbooks/00_install_zabbix_agent.yml
@@ -105,6 +105,7 @@
       ansible.builtin.lineinfile:
         path: "{{ zabbix_agent_cfg }}"
         insertafter: '^# UserParameter='
+        regexp: "^UserParameter=system.certs.*"
         line: "UserParameter=system.certs,python3 /share/ZFS530_DATA/.qpkg/ZabbixAgent/cert_check2.py"
       when: inventory_hostname == 'nas.home.lan' or inventory_hostname == 'm-server.home.lan'