Watchdog Error message while it's running

[NetEye]

I have successfully Watchdog running and also have it automatically start up after a restart.
Only one problem accused after: sudo systemctl status watchdog -l
It contains a message: "cannot open /dev/watchdog (errno = 16 = 'Device or resource busy')" at one of the rows.
See the picture for details.
So I can see watchdog is running and also starts after a restart.
Can anyone help me to solve this.
Looking on Google did not give me the solution.
regards