I cannot get the Cisco VPN client 4.0.2 to connect with Cisco Secure ACS 2.6 through a pix firewall. A secure connection can not seem to be established and the connection just seems to hang for a while and then prompt an error saying that it can't connect. However if I prompt with an invalid userID or password, Cisco secure will imediately not authorize the connection. I'm thinking there might be compatibility issue between the 2 versions of software and I need to upgrade to a later version of ACS. Can someone point me in the right direction to resolve this issue?