If your 4G router is unable to detect the SIM card or get the error message of “SIM card unavailable”:
Firstly please verify if the SIM card is inserted correctly. Refer to SIM card guidance.
Secondly please check if the SIM card is clean especially on the golden contacts.
If there is dust/dirt/oil on the SIM card, you can follow the below tips to clean the SIM card.
- You can wipe the gold SIM card contacts gently with a soft cloth to remove any dust or oils.
- If unable to clean the specks of dirt, use a soft rubber pencil eraser to clean the gold SIM card contacts, and use a soft cloth to wipe away any eraser residue.
- The old SIM card might have oxidation on the golden contacts. You can use rubbing alcohol to remove oxidation. Dampen one end of a cotton swab with rubbing alcohol. Then gently rub the alcohol against the gold contacts on your SIM card. Continue cleaning the contacts until all of the oxidation is gone.