Feel free to look around and see what services and devices the monitored servers have.
System shows the current status of the monitored services and devices on the host.
Everything is fine. Something is not quite right, but the system has not yet reached a critical state. Something serious is wrong with the host. By selecting one of the shown hosts you will be taken to a page that holds detailed information about the services and devices being monitored on the host. Services shows the current status of the monitored services, e.g. web or mail server.