An ASP.NET setting has been detected that does not apply in Integrated managed pipeline mode.
For details on how to register WCF with IIS and ASP.NET?
2. Secondly, Open IIS and go to Advanced Settings of your website/virtual directory. In “Advance Setting” popup, change the Application Pool to “Classic .NET AppPool” and click ok.
Important thing to remember is that the Application Pool that is being used by our application should have two important settings.
a) Managed Pipeline Mode of AppPool should set to “Classic” instead of “Integrated”.
b) .NET Framework Version of AppPool should be the same we used for the WCF service.
Having these two settings, we can create and use a new AppPool for our application and we don’t need to be specific to “Classic .NET AppPool”.