My iphone 6 plus could not activate cellular data network
Hello,I cannot connect to internet with my iphone 6. I have this message ''could not activate cellular data network '' when I using safari. its won't work. I already reset network , restore or anything (http://support.apple.com/en-us/HT201415) . But its shown "at&t 4g" on the top of the screen and I can makes call and send text messages.
Do I have to go ATT store to change sim card?
Please help me!