My smartphone does not recognize the SIM... here is how to fix it! A phone that does not recognize the SIM card (or "chip" as it is commonly known) is a common and rather annoying problem. There are several possible causes for this, and some "detective work" is needed to determine the exact culprit.
Fortunately, most cases have a simple solution. So if your smartphone does not recognize the SIM card, you may find the solution below.
- 1 The phone does not recognize the SIM ... here is how to do it!
- 2 If the phone does not recognize the SIM, try cleaning the contacts on the card
- 3 Test your SIM on another phone
- 4 If the phone does not recognize the SIM, try another SIM on your smartphone
- 5 If you've recently updated your device, try this
The phone does not recognize the SIM ... here is how to do it!
Do you use an adapter? Try to change it
Adapters are quite common among smartphone users. They allow you to use a SIM card format (such as a Nano-SIM) on a smartphone that requires another format (such as a micro-SIM or a "normal" SIM).
So common, in fact, that if you go today to a telephone operator and buy a SIM card, you will probably get a "triple-cut" card with a Nano-SIM surrounded by two plastic frames, the adapters are suitable for smartphones that use other formats.
Since they are simply thin plastic pieces, the adapters can wear out or become deformed over time, causing the board to become misaligned with the internal contacts of the device, which will not be able to recognize it.
The solution is simple: replace the adapter. This is quite common. But if it doesn't work ... keep reading.
If the phone does not recognize the SIM, try cleaning the contacts on the card
Dirt on the card's gold contacts can also cause problems. A simple solution for this is to take a hard white school gum and rub it gently on the contacts until they are shiny again. This should be sufficient to remove any accumulated oxidation.
An alternative is to use a cotton ball soaked in a drop of isopropyl alcohol instead of 99% or more instead of rubber. Once again, gently rub the cotton swab over the contacts and wait for the alcohol to evaporate completely before reinserting the card into the smartphone.
Warning: in this procedure never use alcohol for alcohol or "domestic" alcohol. These products contain large amounts of water (30 to 54%!), which can cause more oxidation and aggravate the problem. And never apply alcohol directly to your smartphone.
Has it not yet worked? So ... let's proceed!
Test your SIM on another phone
It's easy: remove the card from your smartphone and insert it into another device, it's the most important advice to listen to. If the SIM is not recognized, it is defective. In this case, go to your operator's store and ask to replace it. This usually costs around € 10, you don't have to wait more than a few minutes.
If the card works on another device, the defect could be on your smartphone. In this case ... go ahead.
If the phone does not recognize the SIM, try another SIM on your smartphone
Put a SIM that you know works on another device on your smartphone. It should be recognized. Otherwise, it is very likely that the defect is in your device: the contacts between the card and the phone pins could be deformed, compromising the connection. In this case, the best thing to do is call the manufacturer's technical support.
Some suggest placing a piece of paper or thin cardboard behind the card before inserting it into the device. The idea is to make the card more "thick" and force it against the contacts. Never do it!
If your smartphone has a "drawer" slot, you risk jamming the card (with paper and more) in the slot and causing even more damage. And if the device uses a slot "lock" or "swing" you could end up forcing the mechanism, and therefore you will not be able to use it.
If you've recently updated your device, try this
It is not common, but it happened to me: if your smartphone has stopped recognizing the card exactly after a system update, something could have gone wrong during the process and cause the problem. In this case, in addition to the previous suggestions, try performing a factory reset.
The idea is to remove any configuration or parameter residue from a previous version of the system that is harmful to its operation. In this process, all the data from your device will be deleted and will behave as if they had just come out of the box with all the settings restored to their default values. The difference is that it will continue to run the new version of the operating system.
To restore, go to Configure/Backup and Restore/Restore original. Click on Reset phone and wait for the process to complete. But first, back up all important data and applications on your device as they will be deleted.
Here is a little help:
- Best Android backup app - How to do Android Backup 
- How to format your phone [Android hard reset]
If all this has not worked, then you have to take it to a service center. Prepare your smartphone, take the bill and a dose of patience. I hope your device works soon.
Have you ever had a similar problem? What did you do to solve? Share your experience in the comments below.