Classes residing in App_Code is not accessible

I have created a website in ASP.NET and have created a class and put it inside of the App_Code folder. However I cannot access this from my other pages. Does something need to be configured to allow this? I have made it work in previous projects, but not in this one, somehow.

namespace CLIck10.App_Code
{
    public static class Glob
    {
        ...
    }
}