The BIG-IP ASM System is configured with a virtual server that contains an HTTP class profile and the protected pool members are associated within the HTTP class profile pool definition. The status of

Assigning a monitor to the virtual server itself is not a standard BIG-IP configuration - monitors are assigned to pools or pool members, not directly to virtual servers.

The HTTP class profile pool's monitor determines traffic-path health but does not drive the parent virtual server's overall availability status, so it remains Unknown.

A fallback host is a redirect destination for unavailable pools and does not provide a health-monitoring path that resolves an Unknown virtual server status.

The virtual server's health status is driven by the default pool assigned directly to it. When the HTTP class profile handles traffic but the virtual server has no default pool with a monitor, the system cannot determine availability. Assigning a default pool with a successful monitor gives the virtual server a health-check anchor, changing its state to Available (Green).