ISA server stops responding the user requests and its required to reboot the ISA server or restart the firewall service.- Scenario2

As i mentioned long time back about scenario 2. I posted this blog on ISA/TMG and its link is https://blogs.technet.com/b/isablog/archive/2011/01/13/random-authentication-prompts-while-accessing-internet-through-isa-server-followed-by-isa-server-becoming-unresponsive.aspx

Please have a read.