Site stopped working in asp.net System.Web.WebPages.Razor.Configuration.HostSection cannot be cast to

Question

I have a problem like this on server

[A]System.Web.WebPages.Razor.Configuration.HostSection cannot be cast to [B]System.Web.WebPages.Razor.Configuration

Answer 1

I found a problem and solution.

1 I target my code to 4.0 and then upload the code and it's worked. Before it I also update my code to asp.net MVC 4.

now it's work :)