The “critical” status would mean there are no backends available to deliver the traffic. You could disable temporary the farm guardian advanced checks just to confirm the health scripts are not affecting to the status of the backends.
The farm status is controlled by a PID file created under /var/run path. You can check the logs in /var/log/syslog searching for some errors.
Also, feel free to generate a support save via System > Support Save and send it via support@relianoid.com
