I have setup a server. The ports are open. Auth servers are up, but all players cannot access my server.
The message the game gives is:
"Authentification servers are down. Please try again later, sorry!"
The game-log gives this:
http://pastebin.com/Vx3b1Hj8
The server-log gives this:
http://pastebin.com/MSX5dX4j
Your server is being blocked from Mojang's authentication servers and/or session servers.
This is a technical support issue; this site is for bug reports only. For technical support please use the Mojang Support Center.