If your iPhone 8 Plus is displaying a "No SIM" message, it indicates that the device is unable to detect or recognize the SIM card inserted. This issue can occur due to various reasons, such as:
1. SIM Card Displacement: Ensure that the SIM card is properly inserted into the SIM tray of your iPhone 8 Plus. Remove the SIM card, clean it gently if needed, and reinsert it securely.
2. SIM Card Damage: Inspect the SIM card for any visible signs of damage or dirt. If necessary, try using another SIM card to determine whether the issue lies with the SIM card itself.
3. Software Issues: Sometimes, software glitches or updates can cause SIM card recognition problems. Try restarting your iPhone to refresh its software. If the problem persists, update your iPhone to the latest version of iOS available.
4. Carrier Issues: Contact your mobile carrier to confirm whether there are any issues with your SIM card or account. They can check if there are any service disruptions or if there are any configuration problems with your SIM card.
5. Faulty SIM Card Reader: If other troubleshooting steps do not resolve the issue, it's possible that the SIM card reader on your iPhone 8 Plus is faulty. In such cases, it may be necessary to visit an authorized service center or contact Apple Support for further assistance.
Remember to try these steps in sequential order and check after each step if the issue has been resolved.