E not LTE or 3G

Help, my phone is showing E and sometimes showing nothing. I can't make calls, or send imessages. I basically can't do anything! I've had this phone and service for 7 months, no problems until today!
https://straighttalkwirelessforum.com/
https://straighttalkwirelessforum.com/viewtopic.php?f=6810&t=1272175