The "could not activate cellular data network" error means your iPhone won't be able to use the mobile data you're paying for ...

Resetting network settings reinstalls all adapters, erases saved Wi-Fi networks, and custom DNS settings. To perform a network reset, head into Settings > Network & Internet > Advanced Network ...

If you’re experiencing persistent connectivity issues with your iPhone, such as problems with Wi-Fi, Bluetooth, VPN, or cellular networks, resetting your network settings can often resolve these ...

When you install a VPN app, the app automatically adjusts your network settings allowing you to connect with one simple click. But if the VPN isn’t appearing in your network connections, it may be ...