我想要连接ssh://challengeuser@web1.ncc.ninja:2222，但在显示身份验证和下面的示例输出后，连接立即关闭。我可以用来ssh连接其他服务器，但这个不起作用。连接有什么问题？我使用的命令是
ssh challengeuser@web1.ncc.ninja -p 2222
输出（用-vv更新）：
OpenSSH_6.6.1, OpenSSL 1.0.1f 6 Jan 2014
debug1: Reading configuration data /home/shawn/.ssh/config
debug1: /home/shawn/.ssh/config line 1: Applying options for web1.ncc.ninja
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to web1.ncc.ninja [54.84.148.224] port 2222.
debug1: Connection established.
debug1: identity file /home/shawn/.ssh/ncc/id_rsa type -1
debug1: identity file /home/shawn/.ssh/ncc/id_rsa-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.6.1p1 …