Insert sim my l7 wont pick up my sim card keeps telling me to insert sim

Remove the SIM and clean it with soft cloth.
Try the SIM on any other Mobile phone.
You can also try another SIM card on this mobile to make sure the phone is working properly.
If another SIM card is working properly that means the SIM card you are currently using may be corrupt. Its easy to replace a SIM then replacing a phone.
Clean both SIM and phone Connectors then try to insert the SIM.

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