You are correct, there was another 10 crawl failures on the feed. I did another force refresh and it updated successfully. The error is showing another 5XX error, which is an internal error. This could be caused by several things but Spreaker would have to give you some more details as to why the serve would be returning that response.
When you say you don't see any details when you log in to FeedBurner do you mean you don't see the feed at all under your account or the errors associated with it? We don't surface those errors at the moment. It is something we would like to do in the future but I couldn't when or if that will happen.
You should be able to do a manual refresh of your feed, the same thing I'm doing on my end, to get it working again if it errors out. If you log in to FeedBurner and click on the overflow menu on the far right for the feed in question it will have an option to manually refresh it. That will clear all the errors as well so it will start updating again.