In order to conserve battery life, I am in the habit of turning off my mobile network whenever I'm not using it. At home, I have mobile network off, and wi-fi enabled. Over the past several days, I notice that when I try to toggle mobile network to on, it doesn't work. After going in to settings, for mobile network, it says Turning on... After restarting my phone, mobile network always turn on successfully. Why is this!!!