What caused Client Authentication to fail?

Your Rule Base includes a Client Authentication rule, using partial authentication and standard sign-on for HTTP, Telnet, and FTP services. The rule was working, until this morning. Now users are not prompted for authentication, and they see error "page cannot be displayed" in the browser. In SmartView Tracker, you discover the HTTP connection is dropped when the Gateway is the destination. What caused Client Authentication to fail?

A.
You added a rule below the Client Authentication rule, blocking HTTP from the internal network.

B.
You added the Stealth Rule before the Client Authentication rule.

C.
You disabled R71 Control Connections in Global Properties.

D.
You enabled Static NAT on the problematic machines.