neo4J - sandbox doesn't work?
It would appear neo4J (well, the web site) was just totally broken for some days there (around Aug 7 2017).

As reported by wBob, it does seem to be working now!

It's worth noting that the basic problem (reported in the question above) seems to be resolved.  However, after you "create a sandbox" the system appears to fail when you "go to the data browser" in that sandbox ... but it would appear that it simply works after, say, a few minutes (there's no warning while it is getting going).

Once you get past all that it does seem to work, eg the "movie" sandbox: