Samsung Galaxy A5 (2016)
Android 5.1.1
1 Find "Fixed Dialling Numbers"
Press Phone.
Press MORE.
Press Settings.
Press More settings.
Press Fixed Dialling Numbers.
2 Turn on fixed dialling
Press Enable FDN.
Key in your PIN2 and press OK.
3 Turn off fixed dialling
Press Disable FDN.
Key in your PIN2 and press OK.
4 Return to the home screen
Press the Home key to return to the home screen.