You often get the message “Invalid SIM card” when your prepaid card has been deactivated. With older mobile phones, a SIM lock can also be the cause of the problem.
Invalid SIM card: How to solve the problem
If you get a message on your smartphone that your SIM card is invalid, it is probably because it has been deactivated.
- For prepaid cards, this happens if you have not charged them for a long time. In this case, you should contact customer service and ask them to reactivate the card. This is usually possible up to 3 months after the SIM card has expired.
- The error message can also occur if the SIM card is defective. In this case, you can ask the provider to send you a replacement card.
- If you have a contract mobile phone that was purchased before 2015, a SIM lock can also be the cause of the problem. This is where the smartphone is tied to a specific mobile network. As this concept is very restrictive for the user, smartphones with SIM lock are no longer sold today.
- Older used devices may still have a SIM lock, however. You can have this removed free of charge by the provider.
- You need the IMEI number of the mobile phone to unlock it. With this number, you contact the respective provider and receive an unlock code. You then enter this code in your mobile phone.