System.Security.SecurityException: That assembly does not allow partially trusted callers.

Problem

When deploying a website in a shared hosting server, a security exception is thrown as follows.

Server Error in '/' Application.

Description

The application attempted to perform an operation not allowed by the security policy.  To grant this application the required permission please contact your system administrator or change the application's trust level in the configuration file.

Exception Details

System.Security.SecurityException: That assembly does not allow partially trusted callers.

Reason

The shared hosting server where your website is deployed offers a medium level trust for IIS hosting and not allowing partially trusted callers.

Solution

You can override the trust level of the application by adding the following code in the web.config file of your project.