Sometimes, the cellular data network just doesn’t want to play ball with your iPhone. It may not be immediately apparent, but you’ll find out when you try to load a page in Safari, for instance, and the progress bar will get stuck in one place.
To sort this out, you need to try the old, clichéd “turn it off and turn it back on again” approach. Navigate to the Settings app on your phone and turn on Airplane mode (the orange switch at the top of the first settings page). This deactivates everything — the data network, Wi-Fi, GPS, etc. Leave Airplane mode on for around 15-30 seconds and then turn it back off again. This should fix the problem, and get your iPhone back on the Internet again.
If not — you know exactly what I’m going to say now — turn off the iPhone entirely and turn it on again. If, even after doing that, your phone still won’t connect to the Internet, I’d recommend contacting your network provider and asking them if they know what the problem might be.
As a side note, this works just as well with unresponsive Wi-Fi networks. If it’s happening with Wi-Fi, however, you can turn Wi-Fi off by itself by going to Settings > Wi-Fi and turning the switch to off. If that doesn’t work you can try turning the router off and on (if it’s yours), or telling your iPhone to forget the network by tapping the blue arrow in a circle next to the network name and tapping “Forget this network.”
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