Were you able to confirm that it is working for you now?
It was never actually down. It was working fine for us all the way up until we rebooted it. So whatever was happening affected some people and not others. That means the above reports were very helpful in identifying the existence of a problem. Thank you both!
To get technical for a minute, the multiplayer directory server merely lists available sessions. Once you join one, ordinarily everybody within the session is communicating with each other and not the directory server any longer. So if it experiences problems, that should not affect people already in a session. (It definitely would prevent you from rejoining, though, once you are out of the session.)
However, there is one reason it could still affect a session in progress, and that is if any of the participants are connected to each other via the proxy server. As a last resort, if two participants are unable to talk to each other for network reasons, the traffic between them might be routed through the directory server, since both were able to talk to it if they got that far. It acts as a middle man. If any of the players in your session were connected to each other that way, then when the problem began it might have broken that communication. It is conceivable that could destabilize the session for everyone else, especially in a game situation. So perhaps that is part of what you experienced, sundown57.
12oclockhigh, I don't know why RealFlight hung for you when you tried to host. I would expect you to just get an error after a time and for it to otherwise continue on normally.