Just sent a different link in the post above yours...
Can't you have your provider send the settings 'over the air'?
for mine I can just go to their website punch in my details and they send them.
So are the 9th & 10th digits of your SIM card 21, 22, 23 or 24? If they are you need a new SIM card.
There is an "Update settings" button in the SIM settings screen to get the latest provider settings OTA, but it hasn't fixed my LTE indicator yet.
This should work for your internet apn
profile name:internet
APNhone
Username:
Password:
Type of sign in infoAP (should be default)
IP Type IP4v6
proxy server:
proxy port:
Worst case, do a hard-reset without restore and start over. Since you started off having *some* connectivity that will get you back to that point at least while you figure out the LTE thing.
once you add it under the internet apn section in mobile & sim/sim settings it should say activated under the name. if not click it and click the apply button.
What was your phone before, can you check the APN settings on that?
I found out it was only due to being on WiFi. I have no connectivity, and have hard reset. It shows AT&T 4g, but can't use it. Data is enabled.