Another day, another “interesting” issue at a customer. After deploying our product we were left with a partially working web application. The product has been developed over many years and is a mix of ASP Classic, Web Forms, MVC and Web API. In this case ASP Classic pages were broken and would throw an error.
Ensuring ASP Classic is configured properly
The first step is to ensure that IIS has been configured to execute ASP Classic and this is done easily by adding a dummy ASP page to the web application. After deploying this page I was able to confirm that it was working as expected.