Connectivity verifiers specifying an HTTP GET request as the verification method can only run if a firewall policy rule allowing HTTP or HTTPS traffic from the Forefront TMG computer is available. Currently, the appropriate system policy rule is not enabled. As a result, the connectivity verifier may not be able to run. You do not have the permissions required to enable the system policy rule allowing HTTP or HTTPS traffic from the Forefront TMG computer, or to create a firewall policy rule for this purpose.
Contact your Forefront TMG Enterprise Administrator for details about your Forefront TMG administrative role. For more information about Forefront TMG administrative roles, see About Forefront TMG roles and permissions and Configuring roles and permissions in the Forefront TMG Help.
For more information about system policy, see About system policy in the Forefront TMG Help.