The heartbeat monitor is reporting an "Unknown Agent Status (-1)". What do unknown and -1 mean?

An unknown status means that the service control manager on the remote host did not return any valid service status.

This usually happens under the following circumstances:

• The remote computer is running an operating system other than Windows.
• The remote computer is unreachable (e.g. turned off, firewall etc.).
• The network connection to the remote computer is too slow

The message being logged is:

Host MYHOST.COMPANY.COM (THE GROUP) changed its Agent status from OK to ERROR. The reason for the status change was: "Unknown Agent Status (-1)".