My Nexus 5 just recently lost service. Yesterday it worked fine, and I usually have full signal. But today I have no signal at all. I can receive WI-FI though. I've tried rebooting, AirPlane mode Off/On, Settings>Network,Mobile networks, and tried to connect to Koodo but it says "Cannot connect to network." I can see my IMEI but my APN list is gone. What could be a the problem? Please Help.