New iPhone 6s cell data not working?

I bought a used iPhone 6s and the phone works perfectly but i brought over my sim card from my old phone
(iPhone 5) and the cell data doesn't work. Wi-Fi, calling, texting works just not data. It shows 4G on the top but any application that requires internet does not work. I've tried many "fixes" like restarting, reseting, take out sim card, airplane mode, etc. But nothing has worked. Anything else I can do?

BTW the cell data worked perfectly on my old phone. And for whatever reason if you need to know, the carrier is H20 which is a sub brand from AT&T

It may not be on your end of cell data it may be something wrong on your providers end. Id call them when can n see what's going on

If everything else works, you probably need to update the APN (Access Point Names) settings. These settings tell the phone where to look (on the internet) to reach the server for your wireless carrier.

In Android, you have to enter the settings manually, but for iPhones, there's a website that will make the changes for you (since Apple made it rather difficult for the consumer).

unlockit.co.nz

Then simply follow the prompts.

Whenever you are using a phone that was sold through a carrier other than the one you are using it on, sub carriers included, you need to edit the APN settings to get cellular data and MMS (which uses cellular data) to work properly. So call up tech support or visit the current carrier's support website to get the APN settings, enter them and you should be off to the races.