I changed SIM card during my trip to overseas and switched back to my original phobic mobile SIM card yesterday. However, I cannot use Internet. What do I need to do to make it work again?
my situation is:
—i use iPhone 6S
—my IOS is the latest, and I tried restarting the phone but didn’t work
—celler data is on and I can make phone calls
—i received an error message says “cannot activate celler service” when I updated my IOS