I got this error while trying to redirect my display to the local host.
marius$ ssh -X oracle@rac1 Warning: the ECDSA host key for 'rac1' differs from the key for the IP address '192.168.100.101' Offending key for IP in /Users/marius/.ssh/known_hosts:10 Matching host key in /Users/marius/.ssh/known_hosts:13 Are you sure you want to continue connecting (yes/no)? yes oracle@rac1's password: X11 forwarding request failed on channel 0 Last login: Mon Apr 25 18:02:35 2016 from 192.168.100.1 [oracle@rac1 ~]$
The solution that I’ve found is this one: just set the X11UseLocalhost to “no” (in my case was set to “yes”):
vi /etc/ssh/sshd_config ............... X11Forwarding yes #X11DisplayOffset 10 X11UseLocalhost no ................