After upgrading my server to Alpha 16, I'm not able to connect. I've opted in to the experimental build on Steam and I've set my server to Procedural (experimental). But the game client fails with "could not retrieve information from server".
I can connect via FTP and telnet, so it's not a network visibility issue, and I've been playing on this server for months.
I even reset my server "to factory" with no change.