Could not activate cellular data network on iphone 3g

Question

my phone's screen broke yesterday so i bought an iphone 3g from a frend of mine, its running on 4.0.1, i am already on at&t an have an existing data plan but when i try to use the internet i keep gettng this message "could not activate cellular data network" what do i need to do to fix this?

Answer 1

I am absolutely getting LTE.  From the iPhone 5S on, the GSM and CDMA phones had identical GSM radios ostensibly for overseas use (in the case of the Verizon phones).  Verizon tells you they're only unlocked for overseas so that you won't leave their service for a domestic GSM.  Actually, all of the 6's have identical receivers, however the CDMA antennae are disabled on the T-Mobile and AT&T versions... which doesn't matter anyway because Verizon and Sprint won't activate devices that did not originate on their networks though theoretically you could run on Verizon LTE with a GSM only phone as GSM is required for LTE (thus the SIM card in later model Verizon phones).
The Verizon model is the best of everything because it is completely unlocked for any carrier (except Sprint, but who cares, right?).
Edit:  forgot to mention... Verizon is required to make all of their LTE phones GSM-unlocked as per their agreement with the FCC when they were acquiring LTE technology.