How do I upload a document to the product page without it saying it can't support it?

[LillianJiang]

So I've been trying to upload my E-book I started working on a few months ago, but every time I tried to upload it whether that was through URL or etc., it kept saying that the file couldn't be supported. To be fair, its about 215 pages and is 3.03 MB. Is there any way I can upload it for people to buy and download?