I can't play online. I can only play solo. I have bought Minecraft so it should work fine, but, when I try to connect to a server, it says:

Internal client error: java.net.UnknownHostException: session.minecraft.net

I have tried over 20 different servers and it says the same thing for every single one.

Note: These are not Hamachi servers. I'm attempting a direct connection.

  • Your copy of MC can't communicate with the servers for whatever reason. This sounds like more of an issue with your network connectivity than with the game.
    – fredley
    Jul 4, 2012 at 16:28
  • 5
    UnknownHostException is thrown when DNS cannot resolve an IP address. It is usually due to issues with your DNS, proxy, or firewall. Try connecting to a server using the IP address directly. Jul 4, 2012 at 18:21
  • Why would Hamachi influence it? I'm just curious, I don't know all too much about these things myself.
    – The Ugly
    Dec 20, 2013 at 7:00

1 Answer 1


Quote from Kristoffer Jelbring, the Mojang web guy: "If you get an UnknownHostException when trying to join a MC server your DNS record is most likely outdated."

See this link for instructions on refreshing your DNS.

Source: Twitter @KrisJelbring

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