- This error can occur when IIS is installed after installing .NET Framework 4, or if the 3.0 version of the WCF Http Activation module is installed after installing IIS and .NET Framework 4.To resolve this problem, you must use the ASP.NET IIS Registration Tool (Aspnet_regiis.exe,) to register the correct version of ASP.NET. This can be accomplished by using the –iru parameters when running aspnet_regiis.exe as follows:1- Open Visual studio command prompt.2- write this command aspnet_regiis.exe -iru
