Download text file without extension issue

Hi I need to download file that does not have extension. The file itself is a simple plain text file. I do this from code using WebClient object. I also cannot view this file in browser with the same error.The error was 404 - file not found. After research I added mime type: .* as application/octet-stream on web server level. Also the file has these permissions: NetworkService - full access, ASP.NET - full access. Rebooted machine after making changes. Still the same issue. Anybody can advise what else to look for? Thanks a lot, Roman