Hi Raghavendra,
The is common issue if you choose to run Classic ASP and ASP.NET together since ASP.NET doesn't share session data with Classic ASP web application. Although you were able to redirect login pages in Classic ASP for authentication, the ASP.NET web application won't aware of the session data after authentication. There are synchronous mechanism like using Single Sign On for different applications, you can check if it is suitable for your web site.
Zhao Ji Ma
Sincerely,
Microsoft Online Community Support
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