Well, "problem solved" may be an exaggeration. You may have "task accomplished", but problem still present.
I suspect that what you really wanted to do is to reload the configuration files, and that gets done with "rndc reload". But you still have a lingering problem: for some (unknown) reason, stopping and starting the current named server is not working. That might be a one-time confusion which goes away after the next reboot, or it might be a systemic problem that will come back to bite you. On my system, I would still debug the underlying reason it went wrong. A good starting point would be the steps Zirias suggested to kill the currently running instance, then verify that "service named start" and "service named stop" work a few times in a row.