I've got an old, Classic ASP application that is now running on Windows 2012R2 under IIS8.5. I've created a custom page to handle 500 errors, and used httpErrors configuration to reference it when an error occurs in any of the .asp pages within the application.
However, when the custom pages executes and attempts to retrieve the details of the last error with Server.GetLastError(), it is essentially blank, so I can write nothing useful to a local logfile or in any Email.
I've spent hours looking for useful "hits" from search engines, but so far I've not managed to find a working solution to this, despite many different attempts and clues, usually from people who encountered this when they first migrated from IIS6 to II7.
Would appreciate any useful tips or pointers, especially with reference to to configuration in the relevant XML files. Thanks in advance.