OL7 xclock - Error: Can't open display: :10.0

Hi all,

I have no idea why xclock did not work. settings are the same as in another host which works.

• check sshd_config, x11forwarding = yes,
• systemdctl also shows sshd service enabled
• tried display 0.0, 10.0 etc.... not work
• check x11 library exists
• check mobaXterm settings x11 forward enabled
• check /etc/hosts
• despite all these config which seems correct, after logon server, shows x11-forward disabled or not supported

[root@linux7-11b ~]# grep -i X11 /etc/ssh/sshd_config <<<---

X11Forwarding yes

#X11DisplayOffset 10

#X11UseLocalhost yes

#    X11Forwarding no

[root@linux7-11b ~]# export DISPLAY=:10.0 <<<---

[root@linux7-11b ~]# xclock