*Restart your phone and see if that fixes your problem as it often resolves many minor glitches. Method 1. Press and hold the 'Volume Down' and 'Power' buttons at the same time for at least 7 seconds. Your device should restart after this. Method 2. Using two fingers, swipe down from the top of the screen to open the Quick settings panel. Tap the 'Power' icon, and then tap 'Restart'. Tap 'Restart' again to confirm.
*Inspect the SIM card Turn off your phone by pressing the Power button and take out the SIM card from the SIM card tray. Check for any visible signs of damage like scratches or stains. Clean the SIM card and tray with a clean, dry cloth. Reinsert the SIM card, making sure it is properly installed in the tray.
* Reset network settings Try to reset network settings: Settings > Scroll to and tap "General management" > Tap "Reset" > "Reset network settings." > Reset Settings and Reset.
Insert the SIM card into another phone and see if it gets detected. If the SIM card is also not detected by another phone, then the SIM card is already damaged. We recommended contacting your service provider for assistance and replacing your SIM card with a new one.
