Phone not detecting SIM

Basic troubleshooting for a Samsung Galaxy J7 Prime not detecting SIM:

1. Test the SIM card in another phone – if it works there, the issue is with your phone.

2. Clean the SIM card and tray – use a dry cloth or a cotton swab with isopropyl alcohol.

3. Restart the phone – sometimes the SIM is detected only after reboot.

4. Check SIM settings – go to Settings → Connections → SIM card manager.

5. Try another SIM card – to rule out a faulty SIM.

6. Software – update the phone, or perform a factory reset (back up data first).

7. Hardware – if none of the above works, the SIM reader may be worn out or defective. Fixing it requires replacing the SIM slot or motherboard.