From my experience, if the site goes down mid-roll, that roll usually doesn't go through.   That has happened to me like 3 or 4 times. 

I only started playing a few days ago though.   I have had trouble the entire time when trying to connect from iphone or google nexus.   Even when the site was up on my laptop, I was unable to access it from a mobile device.   Is this a known issue, or is it something on my end?