This Article applies to

4G/5G Routers, MiFi, 4G/5G Deco models

Occasionally, there was feedback that the router fails to detect the SIM card after long-term use. This problem often appears randomly; for example, the router may suddenly show “No SIM card detected” even though the card was working properly before. After inserting it into another device or reinserting it multiple times, the SIM card can be correctly detected. If we check the SIM card carefully, its metal contacts appear dull, spotted, or slightly discolored.

Here are some advices to avoid oxidation/contamination on the SIM card and keep a reliable SIM card detection.

If your router occasionally fails to detect the SIM card, cleaning the card contacts may help restore proper operation.

Method 1: Soft Tissue Cleaning

• Power off the TP-Link router and remove the SIM card carefully.
• Fold a clean, soft paper tissue several times to make it thicker and smoother.
• Lightly press the paper with your fingernail to clean the contact surface of the SIM card.
• Make sure no fibers or debris remain on the surface before reinserting the card.

Method 2: Eraser Cleaning

• Use a clean, soft pencil eraser (preferably a white, non-abrasive type).
• Lightly rub the SIM card contacts a few times to remove the oxidation layer.
• Wipe the contacts again with a clean tissue to remove any eraser dust.
• Reinsert the SIM card and restart the router.

⚠ Do not use metal tools, abrasive materials, or strong solvents, as these can damage the gold plating and worsen the problem.

More Advice to minimize recurrence:

• Avoid touching the SIM card contacts with your fingers.
• Store unused SIM cards in a dry, dust-free container or anti-static bag.
• Keep your TP-Link router in a cool, dry environment away from humidity.
   

If the router still fails to detect the SIM card after cleaning, please refer to SIM Card not Found? for more advice.