Pi companion computer

after doing setup as mentioned in the documentation
When iam trying to connect my companion computer( pi3 ) working as apsync with the desktop via putty via LAN
I entered the IP address of the pi in that putty and login and password as mentioned but after 5 to 6 seconds the putty is stopped working showing error (fatal error: software connection is abort)…
Can you figure the problem with my setup
Thank you