Why data isn’t working

Here are a few things you can try to fix the problem:

1. Make sure that cellular data is turned on. Go to Settings > Cellular and make sure that the Cellular Data switch is turned on.
2. Check your coverage. If you're in an area with poor cellular coverage, your data might not work. Try moving to a different location to see if that fixes the problem.
3. Restart your iPhone. Sometimes, a simple restart can fix minor software issues. To restart your iPhone, hold down the power button and the home button at the same time until you see the Apple logo.
4. Reset your network settings. This will reset all of your network settings, including your Wi-Fi networks, passwords, and cellular settings. To reset your network settings, go to Settings > General > Transfer or Reset iPhone > Reset > Reset Network Settings.
5. Update your carrier settings. Your carrier may have released an update that fixes the problem with your cellular data. To update your carrier settings, go to Settings > General > About and tap on Carrier. If there's an update available, it will be downloaded and installed automatically.
6. Take your iPhone to an Apple Store. If you've tried all of the above and your cellular data is still not working, you may need to take your iPhone to an Apple Store for further assistance.

Official Apple Support

I hope this helps!