CMK version: CFE 2.1.0p9
OS version: Rocky Linux 8.6
Error message: No message but all services are vanished after activating the graylog integration for that specific host.
I tested on another host with the same result. When I remove the integration, all services are back.
EDIT: solved it by changing the hosts Checkmk agent / API integrations to "Configured API integrations and Checkmk agent