Register the service node in the Hosting Panel task is failed. Service node is hosted on Parallels virtual machine or Parallels Virtuozzo container.
The error 'SSL certificate problem, verify that the CA cert is OK. Details: error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed' occurred during the connection to the agent at 'https://18.104.22.168:8443/agent.cgi'.
Offline Management is enabled for the virtual machine/container. As Offline Management service and PA Agent operates on the same port
8443/tcp, requests from PA Management Node are handled by VZ agent, not Plesk Automation.
Login to Hardware node (or PCS/VZ) node and disable Offline management:
prlctl set <ID | NAME> --offline_management no --save
vzctl set <ctid|name> --offline_management no --save