Recently, my data switched from LTE to 3G. While 3G is on (not using Wi-Fi), there is no actual connection and I can't access the Internet at all. I first thought it was my plan, but still have a whole ton of data left. I put my SIM card in my family member's phone and it automatically went to LTE, which worked, but not on my phone. I have tried basic tried troubleshooting methods like Airplane Mode, Reset Network Settings, etc. to no avail. I currently use an iPhone 7 Plus and it worked completely fine before with no problems with all. Would be a pleasure for LTE to work again. 🙂
