The source code that generated this unhandled exception can only be shown when compiled in debug mode. To enable this, please follow one of the below steps, then request the URL:

1. Add a "Debug=true" directive at the top of the file that generated the error. Example:

<%@ Page Language="C#" Debug="true" %>

i don't get where to put the debug=true

C:\Users\User\Desktop\Documents\BB.pdf

Where would I put it here

To enable debug mode in your source code, you need to add the "Debug=true" directive at the top of the file that generated the error. Here's an example of where to add it:

If you are working with a web application, you should look for a file with a ".aspx" extension, typically in the "Views" or "Pages" folder of your project. Open the file and add the following line at the top:

```csharp
<%@ Page Language="C#" Debug="true" %>
```

Make sure to place it before any other code or HTML tags in the file.

If the error occurred in a different type of file (e.g., a class file or a script file), you don't need to add the "Debug=true" directive. Instead, you may need to modify your project settings to enable debug mode.

Once you have made the necessary changes, save the file. Then, to see the source code that generated the exception, you can request the URL again. The error message should display the new details if debug mode is successfully enabled.