debug3: channel 2: status: The following connections are open:
  #1 client-session (t3 r-1 i0/0 o0/0 fd 6/7 cc -1)
  #2 mux-control (t16 r-1 i3/0 o3/0 fd 9/9 cc -1)

Trying open2pty
opening Telnet
debug1: multiplexing control connection
debug2: fd 9 setting O_NONBLOCK
debug3: fd 9 is O_NONBLOCK
debug1: channel 2: new [mux-control]
debug3: channel_post_mux_listener: new mux channel 2 fd 9
debug3: mux_master_read_cb: channel 2: hello sent
debug3: mux_master_read_cb: channel 2 packet type 0x00000001 len 4
debug2: process_mux_master_hello: channel 2 slave version 4
debug3: mux_master_read_cb: channel 2 packet type 0x10000004 len 4
debug2: process_mux_alive_check: channel 2: alive check
debug3: mux_master_read_cb: channel 2 packet type 0x10000002 len 69
debug2: process_mux_new_session: channel 2: request tty 1, X 0, agent 0, subsys 0, term "xterm-256color", cmd "", env 1
debug3: process_mux_new_session: got fds stdin 10, stdout 11, stderr 12
debug1: channel 3: new [client-session]
debug2: process_mux_new_session: channel_new: 3 linked to control channel 2
debug2: channel 3: send open
debug3: send packet: type 90
debug3: receive packet: type 91
debug2: channel 1: open confirm rwindow 12288 rmax 512
debug3: receive packet: type 1
Received disconnect from 10.10.3.6 port 22:2: Disconnect Protocol error
Disconnected from 10.10.3.6 port 22