Specified machine key not used

[NETAWEY]

I'm trying to develop SSO authentication between 2 web applications, application A and application B. When a user tries to access application B, he will be redirected to the login page of application A. After he logs in, he is still being redirected to application A login page.After some investigation, I found out that application B cannot decrypt the authentication cookie created by application A. I have specified the same machine key in application B and A web.config. But when I run this code:\[code\](System.Web.Configuration.MachineKeySection)System.Web.Configuration.WebConfigurationManager.OpenMachineConfiguration().SectionGroups["system.web"].Sections["machineKey"];\[/code\]It gives me AutoGenerate,IsolateApps. Is there any other setting that can overwrite the machine key section in web.config? How do I fix this?Thanks!