新安装的 Ubuntu Server 16.04，已完成更新和升级。运行sudo service ssh status表示它已启动并正在运行。我在安装过程中标记了 OpenSSH-server。
但我无法从我的 OS X 计算机连接到该机器。
当我尝试连接时，发生了以下情况：
OpenSSH_6.9p1, LibreSSL 2.1.8
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 21: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to 192.168.1.90 [192.168.1.90] port 22.
debug1: Connection established.
debug1: identity file /Users/mattias/.ssh/id_rsa type 1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/mattias/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/mattias/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/mattias/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/mattias/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/mattias/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/mattias/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/mattias/.ssh/id_ed25519-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.9
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.2p2
Ubuntu-4ubuntu1
debug1: match: OpenSSH_7.2p2 Ubuntu-4ubuntu1 pat OpenSSH* compat 0x04000000
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to 192.168.1.90:22 as 'admin'
debug1: SSH2_MSG_KEXINIT sent
然后它就什么都不做了。就挂在那里。服务器上的 auth.log 中没有太多事情发生。过了一会儿，它显示Connection closed <ip> [preauth]。
这是什么情况？非常感谢您提供协助。