If Android does not see the SIM card, the phone does not connect to the network, and "No SIM" appears in the status bar. Most often, the reason is due to the slot, SIM card, or device settings.
Below are the quick fixes.
Method 1: Checking the SIM card
- Turn off your phone
- Remove the SIM card
- Clean the contacts with a dry cloth
- Plug it back in and turn on the phone
Method 2: Checking the SIM slot
- Try to insert the card into another slot (if the device supports Dual SIM)
- Try another SIM card to avoid card damage
Method 3: Reset Network settings
- Open Settings → System → Reset → Reset Network Settings
- Confirm the action
- Restart your phone
Method 4: Turn airplane mode on and off
- Activate Airplane Mode for 10-15 seconds
- Turn off airplane mode
- Check the appearance of the network
Additional reasons
- The SIM card driver in the system is corrupted
- Incorrect firmware updates
- The phone is blocked by the operator
- Hardware failure of the SIM slot
Bottom line
Most often, the problem is solved by checking the card and slot or resetting the network settings. If the SIM card is working properly, but the phone still does not see the network, a hardware problem is likely.