Ansible unknown SSH error

    "msg": "ERROR! SSH encountered an unknown error. The output was:\nOpenSSH_7.2p2 Ubuntu-4ubuntu2.1, OpenSSL 1.0.2g-fips  1 Mar 2016\r\ndebug1: Reading configuration data /home/matteo/.ssh/config\r\ndebug1: /home/matteo/.ssh/config line 5: Applying options for *\r\ndebug1: /home/matteo/.ssh/config line 7: Applying options for *.strato.de\r\ndebug1: Reading configuration data /etc/ssh/ssh_config\r\ndebug1: /etc/ssh/ssh_config line 19: Applying options for *\r\ndebug1: auto-mux: Trying existing master\r\ndebug1: Control socket \"/home/matteo/.ansible/cp/ansible-ssh-ssh.strato.de-22-matteo\" does not exist\r\ndebug2: resolving \"ssh.strato.de\" port 22\r\ndebug2: ssh_connect_direct: needpriv 0\r\ndebug1: Connecting to ssh.strato.de [2a01:238:20a:202:13f0::1] port 22.\r\ndebug2: fd 3 setting O_NONBLOCK\r\ndebug1: fd 3 clearing O_NONBLOCK\r\ndebug1: Connection established.\r\ndebug3: timeout: 9950 ms remain after connect\r\ndebug1: key_load_public: No such file or directory\r\ndebug1: identity file /home/matteo/.ssh/id_rsa type -1\r\ndebug1: key_load_public: No such file or directory\r\ndebug1: identity file /home/matteo/.ssh/id_rsa-cert type -1\r\ndebug1: key_load_public: No such file or directory\r\ndebug1: identity file /home/matteo/.ssh/id_dsa type -1\r\ndebug1: key_load_public: No such file or directory\r\ndebug1: identity file /home/matteo/.ssh/id_dsa-cert type -1\r\ndebug1: key_load_public: No such file or directory\r\ndebug1: identity file /home/matteo/.ssh/id_ecdsa type -1\r\ndebug1: key_load_public: No such file or directory\r\ndebug1: identity file /home/matteo/.ssh/id_ecdsa-cert type -1\r\ndebug1: key_load_public: No such file or directory\r\ndebug1: identity file /home/matteo/.ssh/id_ed25519 type -1\r\ndebug1: key_load_public: No such file or directory\r\ndebug1: identity file /home/matteo/.ssh/id_ed25519-cert type -1\r\ndebug1: Enabling compatibility mode for protocol 2.0\r\ndebug1: Local version string SSH-2.0-OpenSSH_7.2p2 Ubuntu-4ubuntu2.1\r\ndebug1: Remote protocol version 2.0, remote software version OpenSSH_3.7.1p2\r\ndebug1: match: OpenSSH_3.7.1p2 pat OpenSSH_3.* compat 0x01000000\r\ndebug2: fd 3 setting O_NONBLOCK\r\ndebug1: Authenticating to ssh.strato.de:22 as 'matteo'\r\ndebug3: hostkeys_foreach: reading file \"/home/matteo/.ssh/known_hosts\"\r\ndebug3: record_hostkey: found key type RSA in file /home/matteo/.ssh/known_hosts:6\r\ndebug3: load_hostkeys: loaded 1 keys from ssh.strato.de\r\ndebug3: order_hostkeyalgs: prefer hostkeyalgs: ssh-rsa-cert-v01@openssh.com,rsa-sha2-512,rsa-sha2-256,ssh-rsa\r\ndebug3: send packet: type 20\r\ndebug1: SSH2_MSG_KEXINIT sent\r\ndebug3: receive packet: type 20\r\ndebug1: SSH2_MSG_KEXINIT received\r\ndebug2: local client KEXINIT proposal\r\ndebug2: KEX algorithms: curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,ext-info-c\r\ndebug2: host key algorithms: ssh-rsa-cert-v01@openssh.com,rsa-sha2-512,rsa-sha2-256,ssh-rsa,ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,ssh-ed25519-cert-v01@openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-ed25519\r\ndebug2: ciphers ctos: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com,aes128-cbc,aes192-cbc,aes256-cbc,3des-cbc\r\ndebug2: ciphers stoc: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com,aes128-cbc,aes192-cbc,aes256-cbc,3des-cbc\r\ndebug2: MACs ctos: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1\r\ndebug2: MACs stoc: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1\r\ndebug2: compression ctos: zlib@openssh.com,zlib,none\r\ndebug2: compression stoc: zlib@openssh.com,zlib,none\r\ndebug2: languages ctos: \r\ndebug2: languages stoc: \r\ndebug2: first_kex_follows 0 \r\ndebug2: reserved 0 \r\ndebug2: peer server KEXINIT proposal\r\ndebug2: KEX algorithms: diffie-hellman-group-exchange-sha1,diffie-hellman-group1-sha1\r\ndebug2: host key algorithms: ssh-rsa,ssh-dss\r\ndebug2: ciphers ctos: aes128-cbc,3des-cbc,blowfish-cbc\r\ndebug2: ciphers stoc: aes128-cbc,3des-cbc,blowfish-cbc\r\ndebug2: MACs ctos: hmac-md5,hmac-sha1,hmac-sha1-96\r\ndebug2: MACs stoc: hmac-md5,hmac-sha1,hmac-sha1-96\r\ndebug2: compression ctos: none\r\ndebug2: compression stoc: none\r\ndebug2: languages ctos: \r\ndebug2: languages stoc: \r\ndebug2: first_kex_follows 0 \r\ndebug2: reserved 0 \r\ndebug1: kex: algorithm: diffie-hellman-group-exchange-sha1\r\ndebug1: kex: host key algorithm: ssh-rsa\r\ndebug1: kex: server->client cipher: aes128-cbc MAC: hmac-sha1 compression: none\r\ndebug1: kex: client->server cipher: aes128-cbc MAC: hmac-sha1 compression: none\r\ndebug3: send packet: type 34\r\ndebug1: SSH2_MSG_KEX_DH_GEX_REQUEST(2048<7680<8192) sent\r\ndebug3: receive packet: type 31\r\ndebug1: got SSH2_MSG_KEX_DH_GEX_GROUP\r\ndebug2: bits set: 989/2048\r\ndebug3: send packet: type 32\r\ndebug1: SSH2_MSG_KEX_DH_GEX_INIT sent\r\ndebug3: receive packet: type 33\r\ndebug1: got SSH2_MSG_KEX_DH_GEX_REPLY\r\ndebug1: Server host key: ssh-rsa SHA256:FEq+NKLciheDUUoeKGUxofLtx59sHMdxNai/I2zwBOk\r\ndebug3: hostkeys_foreach: reading file \"/home/matteo/.ssh/known_hosts\"\r\ndebug3: record_hostkey: found key type RSA in file /home/matteo/.ssh/known_hosts:6\r\ndebug3: load_hostkeys: loaded 1 keys from ssh.strato.de\r\ndebug3: hostkeys_foreach: reading file \"/home/matteo/.ssh/known_hosts\"\r\ndebug3: record_hostkey: found key type RSA in file /home/matteo/.ssh/known_hosts:17\r\ndebug3: load_hostkeys: loaded 1 keys from 2a01:238:20a:202:13f0::1\r\ndebug1: Host 'ssh.strato.de' is known and matches the RSA host key.\r\ndebug1: Found key in /home/matteo/.ssh/known_hosts:6\r\ndebug2: bits set: 1044/2048\r\ndebug3: send packet: type 21\r\ndebug2: set_newkeys: mode 1\r\ndebug1: rekey after 4294967296 blocks\r\ndebug1: SSH2_MSG_NEWKEYS sent\r\ndebug1: expecting SSH2_MSG_NEWKEYS\r\ndebug3: receive packet: type 21\r\ndebug2: set_newkeys: mode 0\r\ndebug1: rekey after 4294967296 blocks\r\ndebug1: SSH2_MSG_NEWKEYS received\r\ndebug2: key: /home/matteo/.ssh/id_rsa ((nil))\r\ndebug2: key: /home/matteo/.ssh/id_dsa ((nil))\r\ndebug2: key: /home/matteo/.ssh/id_ecdsa ((nil))\r\ndebug2: key: /home/matteo/.ssh/id_ed25519 ((nil))\r\ndebug3: send packet: type 5\r\ndebug3: receive packet: type 6\r\ndebug2: service_accept: ssh-userauth\r\ndebug1: SSH2_MSG_SERVICE_ACCEPT received\r\ndebug3: send packet: type 50\r\ndebug1: Authentication succeeded (none).\r\nAuthenticated to ssh.strato.de ([2a01:238:20a:202:13f0::1]:22).\r\ndebug1: setting up multiplex master socket\r\ndebug3: muxserver_listen: temporary control path /home/matteo/.ansible/cp/ansible-ssh-ssh.strato.de-22-matteo.IDAvdKyPHbN3GmHQ\r\ndebug2: fd 4 setting O_NONBLOCK\r\ndebug3: fd 4 is O_NONBLOCK\r\ndebug3: fd 4 is O_NONBLOCK\r\ndebug1: channel 0: new [/home/matteo/.ansible/cp/ansible-ssh-ssh.strato.de-22-matteo]\r\ndebug3: muxserver_listen: mux listener channel 0 fd 4\r\ndebug2: fd 3 setting TCP_NODELAY\r\ndebug3: ssh_packet_set_tos: set IPV6_TCLASS 0x08\r\ndebug1: control_persist_detach: backgrounding master process\r\ndebug2: control_persist_detach: background process is 3443\r\ndebug2: fd 4 setting O_NONBLOCK\r\ndebug1: forking to background\r\ndebug1: Entering interactive session.\r\ndebug1: pledge: id\r\ndebug2: set_control_persist_exit_time: schedule exit in 60 seconds\r\ndebug1: multiplexing control connection\r\ndebug2: fd 5 setting O_NONBLOCK\r\ndebug3: fd 5 is O_NONBLOCK\r\ndebug1: channel 1: new [mux-control]\r\ndebug3: channel_post_mux_listener: new mux channel 1 fd 5\r\ndebug3: mux_master_read_cb: channel 1: hello sent\r\ndebug3: send packet: type 1\r\ndebug1: channel 0: free: /home/matteo/.ansible/cp/ansible-ssh-ssh.strato.de-22-matteo, nchannels 2\r\ndebug3: channel 0: status: The following connections are open:\r\n\r\ndebug1: channel 1: free: mux-control, nchannels 1\r\ndebug3: channel 1: status: The following connections are open:\r\n\r\nmuxclient: master hello exchange failed\r\ndebug3: fd 0 is not O_NONBLOCK\r\ndebug3: fd 1 is not O_NONBLOCK\r\ndebug3: fd 2 is not O_NONBLOCK\r\nFailed to connect to new control master\r\nConnection to ssh.strato.de closed by remote host.\r\nTransferred: sent 1776, received 1192 bytes, in 0.0 seconds\r\nBytes per second: sent 3363017.6, received 2257160.4\r\ndebug1: Exit status -1\r\n",