When you failed to remote access to you Solaris box using XStart (XManager) and it show error “The remote host may not have X11 Forwarding (or X11 Tunneling) enabled”. This steps will do the trick.
1. log in your solaris box using ssh (putty)
2. Go to /etc/ssh/sshd_config. Just ensure that it has the following:
# X11 tunneling options
If you already have similar parameters, don’t do anything. But if you had to change the config file, it’s time to restart ssh.