There are a lot of reasons why a download might not be working.
1) If your download stops halfway during the download, generally it means your Internet Service Provider has a spotty connection (one that disconnects often). Unfortunately, there's nothing we can do here. You'll have to download it from a better connection.
2) If the download won't start, you may need to try a more updated browser. We recommend the latest version of Google Chrome.
3) If the download is slow, that often means you're not within an area that has a good enough connection to our server. We run our downloads from an ultra-fast Amazon S3 server, but we can't help it if you're in a city that is too far from us or if your internet connection is spotty.
4) If you get a 404 error, please send us a support ticket. From time to time our URLs break (we're human after all!) Send it to us here: http://photowhoa.freshdesk.com/support/tickets/new