Currently, authentication realm health checks on the ProxySG appliance are created on a per-realm basis and not a per-server basis. They report on the status of the last authentication attempt that was performed in that realm. If the ProxySG appliance was able to successfully complete the authentication using either the primary or the secondary authentication server configured for the realm, the realm will be reported as "healthy."
Because the ProxySG appliance is not configured with a valid username and password to attempt to authenticate with, it only reports on user-initiated authentication attempts. As a result, the "perform health check" button doesn't initiate a new authentication request and will not change the health status of a realm. If the realm is unable to perform authentication, this will be reported as soon as the next user request is received by the ProxySG where the authentication attempt fails. The realm will remain unhealthy until another authentication is attempted after one of the authentication servers becomes available again.