If you've ever called your carrier's customer service to activate a prepaid SIM card or troubleshoot a malfunctioning Android ...

Macworld Some iPhones are locked to single cellular networks, especially iPhones bought in the U.S., while others are ...

your SIM card slot is possibly malfunctioning. It's best to just switch to an eSIM if your iPhone supports it. To know whether you have an eSIM-compatible device, navigate to Settings > Cellular.

Short for embedded SIM, eSIM involves activating a mobile network on a SIM card already present in the iPhone for phone calls, text messages, and internet connections.

Open the Settings app. 2. Tap "General" and then ... See our article on removing your iPhone's SIM card to learn how open the SIM card tray. If you still own an even older iPhone, you'll find ...

Open the Settings app on your iPhone ... You should also ensure that the inserted SIM card works with your iPhone, especially if you transferred it from another device. Update your iPhone 4.