Display of larger files fails with infinite spinning weel

Was excited to use the new features of Confluence 5.7, especially the file viewing feature with ability to comment in context.

Everything seems to work fine until you try a larger file (multiple pages). I get a spinning wheel that never ends and it fails to load the file (I've even waited for over 12 hours, overnight, to make sure it wasn't the conversion that was taking too long). I know the file is fine because I can download it back and the thumbnail displayed on the confluence page shows fine.

Tried originally with a docx file, but even "bigger" pdf files don't seem to work either.

Attachment "Screenshot.png" shows what I keep seeing (spinning wheel) as well as a possible cause for the error (Ajax request seems to fail with HTTP 416 - Request Range Not Satisified).

My setup runs on a Windows Server, behind a proxy handled by IIS and the URL Rewrite module.

The following PDF file can be used to try and reproduce the problem:
http://conorlastowka.com/book/CitationNeededBook-Sample.pdf