How to fix error "Xlib: connection to "hostname" refused by server"

If you are facing this issue on second server and everything works fine on first server.

Then do the following :

first$ xauth list $DISPLAY
first.server.com/unix:0 MIT-MAGIC-COOKIE-1 076aaecfd370fd2af6bb9f5550b26926

first$ telnet second.server.com

login:
Password:

second% setenv DISPLAY first.server.com:0

second% xauth add first.server.com:0 . 076aaecfd370fd2af6bb9f5550b26926