When developing srcomp-puppet under Vagrant, or I've also seen this on a Pi, the binding to IPv6 doesn't seem to work for the nginx proxy which seems to want to connect over v4. I'm not sure if that's something about the nginx config in srcomp-puppet, however since the config does work fine for this year's deployed public compbox (without modifications) I'm expecting that it's not.
When developing srcomp-puppet under Vagrant, or I've also seen this on a Pi, the binding to IPv6 doesn't seem to work for the nginx proxy which seems to want to connect over v4. I'm not sure if that's something about the nginx config in srcomp-puppet, however since the config does work fine for this year's deployed public compbox (without modifications) I'm expecting that it's not.