Cronjob to shut down an instance

I tried to stop  my instance from the webshell, it shuts down but my server dashboard / Turnkey hub shows that the instance is still running although it cannot be accessed anymore.

I also tried to stop it from webmin using cronjob. It shuts down but the server dashboard / Turnkey hub still shows that it is running although my instance is not accessible anymore. So I have to stop my instance from the dashboard.

The command I use is shutdown now P

Do we have to use the server dashboard/Turnkey hub to stop an instance, otherwise how can we use cronjob to stop an instance?

Please help.

Thanks