Migrating aspx to mvc issue

Question

I have migrated from aspx page mvc to mvc razor.

I am using form authentication which is authenticated from the parent domain. Forms Authentication across Sub-Domains

<forms name=".auth" 
             loginUrl="http://external.com/Login/Login_form.aspx" 
             defaultUrl="~/Home/Index"
             domain="external.com" protection="All" timeout="30" path="/" 
             requireSSL="false" slidingExpiration="true" cookieless="externalProfile"/>

After authenticated the user, I am redirecting the user. I have cached the application error and checked, the redirection doesnot work.

It always redirecting to the default.aspx which is not there in my project and "The file '/Views/Shared/Site.Master' does not exist."