The issue was due to Virtualizor upgrade
Below is the command you need to execute to kill all process using below command for VNC to work
[root@os1126 ~]# kill $(pgrep -f “/usr/local/virtualizor/enduser/themes/default/novnc/utils/websockify”)
[root@os1126 ~]# kill $(pgrep -f “/usr/local/virtualizor/enduser/themes/default/novnc/utils/websockify”)
kill: usage: kill [-s sigspec | -n signum | -sigspec] pid | jobspec … or kill -l [sigspec]
Now after retrying accessing virtualizor I can see it working fine