There are a few reasons for seeing an "Unknown" Status in the ACP.
The reason you see this message is a lack of communication between the ACP and the server in most cases.
This can be caused by many factors but is generally due to the buffer being overloaded by network traffic. This can be caused by improper use of FTP by users on the machine ,or network communication errors caused by DDOS attacks , failed or interrupted tasks etc...etc.
You will also see this status when a service is being installed or reinstalled...during routine maintenance tasks that run periodically, or during updates/reboots or configuration changes that we could be running.
If you see this status it is best to submit a support ticket and in the subject line add the words "Status Unknown".
In most cases it is only a matter of a support person resetting the monitor process on the machine.