Depending on the Samsung model, the device is switched off differently; on newer models, the power button is linked to the bixby assistant, which means that the device cannot be turned off using the button.
The Samsung device can be switched off via the status bar, and the power button can also be reactivated if desired.
- Open the notification bar
- Tap on the Power-Icon
- Tap on Power off
- Tap again to turn off your phone