DO 的 SSH 无法连接

前段时间 SSH 一直用的好好的，突然就连不上了，于是加 -v 看了下输出：

OpenSSH_6.2p2, OSSLShim 0.9.8r 8 Dec 2011
debug1: Reading configuration data /etc/ssh_config
debug1: /etc/ssh_config line 20: Applying options for *
debug1: Connecting to 107.170.199.131 [107.170.199.131] port 22.
debug1: Connection established.
debug1: identity file /Users/JmPotato/.ssh/id_rsa type 1
debug1: identity file /Users/JmPotato/.ssh/id_rsa-cert type -1
debug1: identity file /Users/JmPotato/.ssh/id_dsa type -1
debug1: identity file /Users/JmPotato/.ssh/id_dsa-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.2
debug1: Remote protocol version 2.0, remote software version OpenSSH_6.0p1 Debian-4+deb7u1
debug1: match: OpenSSH_6.0p1 Debian-4+deb7u1 pat OpenSSH*
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-ctr hmac-md5 none
debug1: kex: client->server aes128-ctr hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Server host key: RSA 21:34:2e:e7:47:1c:cd:29:b7:23:6c:26:7a:af:15:a6
debug1: Host '107.170.199.131' is known and matches the RSA host key.
debug1: Found key in /Users/JmPotato/.ssh/known_hosts:1
debug1: ssh_rsa_verify: signature correct
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: Roaming not allowed by server
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,password
debug1: Next authentication method: publickey
debug1: Offering RSA public key: /Users/JmPotato/.ssh/id_rsa
debug1: Server accepts key: pkalg ssh-rsa blen 279
debug1: read PEM private key done: type RSA
debug1: Authentication succeeded (publickey).
Authenticated to 107.170.199.131 ([107.170.199.131]:22).
debug1: channel 0: new [client-session]
debug1: Requesting no-more-sessions@openssh.com
debug1: Entering interactive session.
debug1: Sending environment.
debug1: Sending env LANG = zh_CN.UTF-8
Write failed: Broken pipe

Google 了一圈回来各种方法都试了，没用。
ping 是可以 ping 通，但就是 SSH 连接不能。
各位 V 友有遇到过吗？