Installing iOS upgrades is an often-overlooked maintenance task that ensures an iPhone runs correctly. Updates are vehicles for fresh aesthetic modifications for many typical users. In reality, that's only one of the side effects of updating. Another key feature of updates is that they may include patches or fixes for vulnerabilities or flaws that have been detected. Normally, iPhones are programmed to download updates automatically and notify you when they are ready to be updated. Go to Settings>General>About to see whether there's a pending update you haven't installed yet.
Replace the SIM card in its slot.
Removing and re-inserting the SIM card will sometimes resolve network issues. Before you remove the SIM card, make sure your iPhone is turned off. Then, while the phone is still turned off, reinsert the SIM card and turn it back on.
Reset the network settings on your iPhone
If the problem persists, the next best step is to reset the network settings. This phase in the troubleshooting process can help with a variety of issues. Resetting your iPhone's network settings will delete all saved Wi-Fi networks and passwords, as well as cellular settings, VPN, and APN information. Follow the steps below to complete this step:
- Open the Settings application.
- Select General.
- Restart by pressing the Reset button.
- Reset the network settings by pressing the Reset Network Settings button.
- When asked, enter your passcode.
- To confirm, tap Reset Network Settings.
