I have a local server using Flask web framework running on my machine. What I want is to load an html file, which is stored in a folder inside the app directory tree, into an iframe. The iframe src points to "fld/file.html", so I'd say that the file is inside scope, but so far I haven't been able to get it to load. I keep getting a "Not Found" error.
What am I doing wrong? Is it a security issue? Can I do it using another approach?