Invalid SIM Card? Here are the 9 Instant Fixes for it!

Kunal Kashyap
8 min readMar 28, 2024

With this ultimate blogspot, we have categorized 11 fixes you can try instantly on any Android or smartphone device to fix the invalid SIM card problem.

But there are causes that you must know before trying to apply those fixes. 23% of people would actually read the causes and then try the fixes, but 23% will be brilliant people who will fix it instantly without letting their expectations down with this blog post.

A functional SIM card is crucial for connecting to a cellular network, enabling you to make calls, send messages, and access the internet. When encountering an invalid SIM card, it’s essential to understand the underlying causes and find appropriate solutions. This article will explore the common reasons behind the “Invalid SIM card” error and provide troubleshooting steps to fix it.

3 Common Causes of an Invalid SIM Card

There are several potential reasons for an invalidated sim card error. Understanding these causes can help you determine the most effective solution. Here are some common factors:

1. SIM Card Physical Damage

Physical damage to the SIM card can result in an invalid SIM error. This includes situations where the card is bent, scratched, or damaged in any way. Additionally, improper insertion of the SIM card into the device can cause connectivity issues.

2. SIM Card Compatibility Issues

Compatibility problems between the SIM card and your device can lead to the “Invalid Subscriber Identity Module card” error. Sometimes, the SIM card may be locked or restricted, preventing it from working with your device. Another compatibility issue can arise if the SIM card size is not suitable for your device’s SIM card slot.

3. Network or Service Provider Problems

Sometimes, the error can be caused by issues related to the network or your service provider. Network outages or disruptions can temporarily render your SIM invalid. Additionally, an inactive or expired SIM card can lead to this error.

How to Fix an Invalid SIM Card on Any Device (Android or iOS)

Moreover, there is a difference between a no SIM card error and an invalid sim card error.

If you encounter an “Invalid SIM card” error, there are several troubleshooting steps you can take to resolve the issue. Follow these steps one by one until the problem is resolved:

Before anything else, like restarting a device or anything, Here are three things to try in the first case when you find yourself with this problem.

Fix 1. SIM ToolKit App

The SIM Toolkit app is an essential app that comes pre-installed on your Android device and is responsible for managing your SIM card’s services. This app lets you access balance inquiries, mobile banking, and other value-added services your network operator provides. Check this alternative of the SIM Toolkit app.

To fix this issue, you need to clear the cache of the SIM Toolkit app. Here is how you can do it:

Step 1: Open Mobile Settings

The first step is to open your phone’s settings app. You can do this by tapping the settings icon on your home screen or app drawer.

Step 2: Select All Apps

Once in the settings app, scroll down and select “Apps” or “Applications.” It will take you to a list of all the apps installed on your phone.

Step 3: Select SIM Toolkit/SIM Card Apps

Scroll down until you find the SIM Toolkit app or any other app related to your SIM card. Tap on it to open the app settings.

Step 4: Clear the Cache and All Data

Once in the app settings, you will see two buttons — “Clear Cache” and “Clear Data.” Tap on both buttons to clear the cache and all data associated with the app.

Step 5: Force Stop the SIM Toolkit/Card Apps

After clearing the cache and data, return to the app list and force stop the SIM Toolkit/Card Apps. This will close the app and ensure that all changes take effect.

Fix 2. Reset Network And APN Settings

If you are unaware, every SIM card uses network and APN settings to configure your phone with the network provider and their carriers.

But when these settings are misconfigured or if you make any changes unsuitable for your smartphone, you likely find yourself in this scenario when you can’t even see the SIM card because your phone will say the sim card is invalid.

Right now, you are in the situation, and to fix it, reset the network settings and APN settings. What it did is it would clear and reset the default setting as your network settings and APN settings. In that way, you would fix sim card issue.

Here’s What Reset Network Settings do Android & iOS

Fix 3. Disable And Re-Enable the SIM Card From Settings

  • Open the Settings app on your phone.
  • Look for the option “SIM Card” or “Mobile Network” and select it.
  • Check if the toggle for your SIM card is turned on or off. If it’s off, turn it on.
  • If you have multiple SIM cards, ensure the correct one is selected as the default for data and calls.

Also read: Instead of Panicking, Fix Emergency calls only; Reasons & Solutions

Invalid SIM Card Additional Fixes

1. Restart the Device

A simple restart can often resolve temporary glitches and connectivity issues. Turn off your device, remove the SIM card, wait for a few seconds, reinsert the SIM card, and then power on your device.

A simple restart would be enough for you to fix the invalid SIM card error on Android.

2. Check SIM Card Contacts

Ensure that the metal contacts on your SIM card are clean and free from dirt or debris. Use a soft, dry cloth to wipe the contacts and remove any accumulated dust gently.

You see a yellow chip on your sim card on the back side of it. You have to wipe it if there is any dust particle, simply why with any cotton cloth or cloth possible and then follow the next step.

How to Quickly Switch Data SIM Cards on Your Android

3. Ensure Proper SIM Card Insertion

Double-check that the SIM card is correctly inserted into the SIM card slot of your device. Ensure it is securely placed and in the correct orientation, as indicated by the device’s instructions.

To ensure whether you insert the sim card correctly or not, I do not doubt your ability, but instead, you should try reinstating your sim card. If there is any error while inserting, it will be fixed.

4. Try Another SIM Card

If you can access another working SIM card, insert it into your device. This will help determine if the issue lies with the SIM card or the device itself.

5. Check for SIM Card Compatibility

Ensure that your SIM card is compatible with your device. If you recently changed devices or received a new SIM card, confirm that it is the correct size and is supported by your device’s specifications.

6. Contact Network or Service Provider

If the issue persists, contact your network provider or service provider’s customer support. They can assist in verifying the status of your SIM card and checking for any network-related problems.

7. Update Device Software

Ensure that your device’s software is current. Software updates often include bug fixes and improvements that can resolve compatibility issues with SIM cards. Check for updates in your device’s settings or system update section.

Advanced Solutions to Fix SIM Card Invalid

If the basic troubleshooting steps fail to fix the error, there are a few advanced solutions you can consider:

  • Replacing a Damaged or Non-functioning SIM Card
  • Unlocking a Locked SIM Card
  • SIM Card Slot Repair

Preventive Measures for Avoiding an Invalid SIM Card

To minimize the chances of encountering an “unfounded SIM card” error in the future, consider the following preventive measures:

  • Handle SIM Card with Care
  • Use Compatible SIM Cards
  • Regularly Update Device Software
  • Maintain Active Network Services
  • Keep the SIM Card Slot Clean


Q: What does “Invalid SIM card” mean?

ANS: The “Invalid SIM card” error indicates that the SIM card inserted in your device is not functioning correctly or is not compatible with your device.

Q: Can I fix a SIM card invalidated on my own?

Ans: Yes, in many cases, you can resolve the “Invalid SIM card” error by following the troubleshooting steps provided in this article.

Q: Why is my SIM card not working even though it’s not damaged?

Ans: Various reasons, such as compatibility issues, network problems, or device software glitches, could exist. Try the troubleshooting steps mentioned in this article to resolve the issue.

Q: How can I unlock a locked SIM card?

Ans: You must contact your service provider to unlock a locked SIM card and follow their instructions.

Q: Will a software update fix the “Invalid SIM card” issue?

Ans: A software update can sometimes resolve compatibility issues and fix the “Invalid SIM card” error. Ensure that you have the latest software version installed on your device.

  • Fix 1: SIM Toolkit App
  • Fix 2: Reset Network and APN Settings
  • Fix 3: Disable and Re-Enable the SIM Card from Settings
  • Restart the Device
  • Check SIM Card Contacts
  • Ensure Proper SIM Card Insertion
  • Try Another SIM Card
  • Check for SIM Card Compatibility
  • Contact Network or Service Provider
  • Update Device Software
  • Advanced Solutions: Replace Damaged SIM Card, Unlock Locked SIM Card, SIM Card Slot Repair


Encountering an “Invalid SIM card” error can be frustrating, but following the troubleshooting steps outlined in this article can resolve the issue in most cases.

I hope you guys find the article helpful.

We have faced an error recently and are trying to fix it. In the first attempt, we fixed the invalid sim card error. The trick was resetting the network settings and clearing the cache and all data of the SIM toolkit app.

These two fixes are my favorite, but if you have any queries, doubts, suggestions, or experience, let me know in the comments below.



Kunal Kashyap

I’m the Founder of Backdroid. Blog to techie and Android enthusiast.