When you change your SIM card and unfortunately, you get an error message that says “Network Locked SIM Card Inserted”. It means that your phone is network locked.
But you don’t need to worry. After, going through this post, you will come to know what is meaning of network locked sim card inserted and what to do unlock your phone from a specific network.
I will be starting with the real user’s practical scenario!
Practical Scenario 1: Samsung Galaxy S5 Users Get Error Network Locked SIM Card Inserted On AT&T Network
Phone (AT&T locked Galaxy S5) worked fine two weeks ago on AT&T network. I have been using it on the Prepaid service for 3 years. Purchased new phone & new SIM, had terrible service, so I am returning new phone. Purchased new SIM card for old phone (the one that was fine 2 weeks ago) from AT&T store, activated online, phone saying Invalid SIM – Network locked SIM card inserted. Source: AT&T Community Forums
Practical Scenario 2: A User Getting Invalid SIM Card. Network Locked SIM Inserted” Error
So i recent did a back up and reset on my android phone. But i didnt know it would reset my carriers network for all carrier use. So now i have no way to reverse that nd keep the same network carrier that im using. And the phone is originaly from the U.S from T-mobile Carrier. I live in Mexico so before it was sent to me, it was Unlocked from the Network Carrier so i can use a Network Carrier from Mexico, wich im using the Company Network called ” Telcel “. Source: Support Google
Just like above example, there are several users reporting such issues that can be found in several forums and community websites.
Also Read: Samsung S21, S21 Ultra Sim Card Not Detected? Here Is The Fix!
Anyway, let us first know about – network locked sim card inserted meaning and then we will be covering the solutions to fix the issue.
Network Locked SIM Card Inserted Meaning
A network locked sim card inserted means that the card is unable to access the network settings or fails to connect to the network service provider.
You can’t use a different carrier or network SIM card, until you get it unlocked by entering 4, 6 or 8 digits unlock code.
And when such a thing happens, you may see any of the following error messages:
- Enter Network Unlock Code.
- Network Control Key.
- SIM PUK Code.
- SIM Network Unlock PIN.
- SIM Network PIN Blocked.
- Network PIN.
- Master Unlock Code.
- And so on…
And this can occur due to several reasons. Some of the main causes are mentioned below.
Also Read: How To Unlock Phone Password Using CMD (Command Prompt)
Causes: Why Network Locked SIM Card Inserted Error Occur?
As earlier mentioned there could be several reasons due to which you might get the network locked sim card error.
Some of the major causes that can result in issue to occur are:
Network/Carrier Lock: The fact is that your phone is been “locked” to its original carrier/network, it means that it can only be used with a SIM card bought from that carrier. If you switch to another service provider, then it might prompt the error, which is most likely the cause of this problem.
Region Lock: A SIM that is region locked is another reason for network locked sim card inserted error which is related to the phone itself. In such a phone, you can use a specific service provider and it can’t be used with any other carrier providers.
AT&T, Straight Talk, Verizon, Vodafone, T-Mobile, Mint Mobile, Tracfone are some of the examples that sell such devices to keep the customer stick to using their network on the device. This process is known as UICC lock, and phone can be used with sim card provided by themselves only.
Besides that, depending on the nation you are in and the carrier you choose, a region lock might be activated. It is not possible to use a phone outside of this region.
Firmware Issues: This mostly happens when you update your phone system or do a significant data restoration and it happens because most of the phones are prone to software bugs and issues.
Mobile manufacturers frequently launch firmware updates that are really good for the security of the device and protect from malware, spyware or hacking attacks.
But, in rare case upgrading the firmware also interferes with the algorithm of the SIM card settings and hence lead to invalid SIM card error on the device.
Other Causes: There are other several causes such as system error, damaged SIM card, physical damage to phone hardware, moisture in the device.
How To Fix Network Locked SIM Card Inserted Error
Fixing the network locked sim card inserted error is not something that requires a particular or high level of technical knowledge.
All you have to do is to follow the solution mentioned below to get rid of the error.
Note: Below mentioned solutions work for all carriers or networks such as AT&T, T Mobile, Sprint, Virgin Mobile, Verizon, Tracfone, EE, giffgaff, Mint Mobile, O2, Tesco Mobile, Straight Talk, Vodafone, Airtel, Jio and so on. Or using Samsung, Motorola, LG, Huawei, OnePlus, ASUS, OPPO, Realme, Fairphone, Meizu or any other brand phone.
Solution 1: Contact Carrier Provider
When you are getting the SIM card network lock error, then simply call or contact your old or previous carrier service provider.
Explain your issue and ask for the PIN or code to unlock the SIM card. They will then give you the code.
But there are some terms and conditions that need to be met first. Or else, they will not give the code. Here are those terms and conditions:
- You might have to use the default carrier for at least 5-6 months. The actual number of months may vary depending on the carrier.
- The payment of the phones needs to be paid in full.
It might also be possible that you have to pay a termination fee, if the payment of the phone is not paid in full.
After receiving the said code, you have to follow these steps:
- Switch off your phone and then insert your new SIM card.
- Restart your device, and upon restart, the device will ask you for the unlock code.
- You need to simply enter the code that you received from the carrier, and you should be able to use it.
Please note, do not type the wrong code or else you will be locked out of your device.
Also Read: How To Remove or Bypass Samsung Screen Locks – [PIN, Pattern, Password or Fingerprints]
Solution 2: UICC Unlock To Unlock Carrier or Region Locked
You can go for UICC unlocking process as it will help you to unlock carrier or region locked smartphones. And thereby, you can use any service provider and get rid of network locked SIM card error.
For example, if you are a Samsung phone users, you can either use Odin tool to flash your phone or use third-party service like UnlockBoot to unlock UICC on the device.
Solution 3: Try Firmware Repair Tool To Repair Firmware Issue
If you are encountering the network locked SIM card inserted error suddenly, just after restoring or updating your device, then it means that error occurred due to corrupt firmware.
To fix the issue, you can either update the firmware of the device or downgrade it to the lower version.
If that doesn’t work, then you can also try firmware repair tool to fix the error. Here I will recommend you try Android Repair for Android users. It will fix the Android system to normal and thereby help you to get rid of network locked SIM card inserted error.
![]() |
![]() |
You can check out the Android repair user guide and see how it works before you try it.
Note: please first take a backup of your device data as you may face data loss.
Also Read: How To Retrieve Blocked Text Messages On Huawei Phone
Solution 4: Try Online Services To Fix SIM Lock Error
There are also several online services available that you can actually use for unlocking your SIM card. These services use the IMEI number of the device for unlocking smartphones worldwide.
We recommend using Canada Unlocking services. They will provide the unlocking code via email. The process is legal as well as very easy. Here follow the steps to unlock network locked SIM card inserted error.
Reach out the online unlocking services.
- Fill out your phone details and IMEI information.
- They will then send the unlock details to your email id.
- You need to insert the new SIM card into the mobile and switch on the phone.
- Enter the sim unlock pin when asked.
- After entering the proper code, an “unlock pin successful” message will appear on your phone screen.
That’s It! Isn’t that easy and simple.
Also Read: How To Get Unblocked From Blocked Contacts On WhatsApp
Solution 5: Unblock SIM PIN For Android Smartphones/Tablets [Only For Verizon]
If your Android phone purchased from Verizon is asking PUK code to unlock locked SIM card, then you can easily do so.
Here is what you need to do:
- If you are a postpaid user, you can get the PUK via the My Verizon site.
- If you are a prepaid user, you can get the PUK code by contacting the customer service.
- Now, make sure that your mobile or tablet is turned on.
- Now from the keypad, enter the 8-digit PUK code and then tap on OK.
- Enter the new SIM PIN (4-to-8 digits) and tap OK.
- Re-enter the SIM PIN and tap OK.
Note: If you enter the wrong PUK code multiple times, then the SIM card will get disabled permanently.
That’s It!
Wrap Up
So, those are solutions that will help you to solve “Network Locked SIM Card Inserted” error. After trying the solutions mentioned above and any one of them worked, then you will be able to use any carrier’s SIM card in your phone.
If the issue is occurred due to firmware fault, then it is highly recommended that you must try Android Repair software to restore the Android system and thereby get rid of SIM lock errors.
Please support us by subscribing to our YouTube Channel.
If this post helped you, then please share it as it can help others as well!
You May Also Like:
- How To Remove or Bypass LG Screen Locks – [PIN, Pattern, Password Or Fingerprint]
- How To Unlock OnePlus With Broken Screen
- How To Recover Data From Locked Android Phone With Broken Screen
- Samsung S23, S23 Plus, S23 Ultra FRP Bypass – The Guide

Max Field is a founder of Recover Android Data. He is an Android lover and loves to write tips, tricks, fixes for errors, data recovery solutions and more related to Android. He has 9+ years of experience in this field.