Go through the ‘Add STS Reference’ process.

1. Service Certificate Location

Make sure you remove the defaults that the ASP.NET MVC 3 project put into your web.config on the <certificateReference> element. StoreLocation and StoreName must be removed. Otherwise you get the following error.

Your <serviceCertificate> element (full path is “/microsoft.identityModel/service”) should be changed from this:

<serviceCertificate>
   <certificateReference x509FindType="FindByThumbprint" findValue="*****THUMBPRINT*****" storeLocation="LocalMachine" storeName="My" />
</serviceCertificate>

…to this:

<serviceCertificate>
  <certificateReference x509FindType="FindByThumbprint" findValue="*****THUMBPRINT*****"/>
</serviceCertificate>

2. Validate Request

Make sure that you add an <httpRuntime> element and set the request validation mode with a value of “2.0”.