I charge my phone at night while sleeping. So, this morning, assuming my phone was fully charged, I attempted to open an email message. All of a sudden, the phone showed zeroed out, showing "4G-LTE" and gave me a message about something not processing. Did I want to wait? If I try to shut off the phone, the "4G-LTE" reappears and flashes every 30 seconds or so... What's happening?