X11 Forwarding using Cygwin ssh got port 6000 Connection refused

I try to forward X11 using Windows 10 machine as the client and a Ubuntu Linux machine as the server. The ssh is running under Cygwin, which contains xinit and xorg. The steps:

1. Turn on the linux server machine.
2. I enabled the forwarding both in the client and server side using sshd_config configuration file.
3. I set display in Cygwin by executing: export DISPLAY=r1:0.0where r1 is the name of the server
4. I enabled access list on the server side: xhost 192.168.1.143
5. Connect to the server from Cygwin using ssh.
6. Run lxterminal application, but got:

r1@r1:~$ lxterminal    debug1: client_input_channel_open: ctype x11 rchan 3 win 65536 max 16384debug1: client_request_x11: request from 127.0.0.1 37184connect r1 port 6000: Connection refused

Is r1 server port 6000 is rejecting? If yes, how so?