I did some tests with a Samsung Galaxy Tab A, everything was fine, I blocked web site, applications all what I need.

But the problem is when I restricted the device defaults settings after a reboot the tablet lost wifi connection and even if I reboot the tablet the wifi did not get back

There is a way to do a hard reset? 

Device Settings
Modify Devices default Settings	:	Restrict
Restore Factory Settings	:	Restrict
Clip Board	:	Restrict
Screen Capture	:	Restrict
USB	:	Restrict
Connections Using USB	:	Allow
Wifi	:	Allow
VPN	:	Restric

Thanks