Both Samsung Galaxy S20 and S21 come with dual SIM support. Although, a lot of users are experiencing problems with the SIM 1 slot in these two device models (and their variants also).
In both Galaxy S20 & S21, users have reported on the Samsung community and Reddit that there was an error called “SIM 1 Not Allowed” when they used the device. Some of them have tried several solutions to this, like clearing the cache, resetting network settings, changing SIM cards, and so on. But none seemed to fix the issue (for some users).
But unlike them, you have this come to read this guide. Therefore you will be able to fix SIM 1 Not Allowed on Samsung S21 or Samsung S20.
First, we will go through the possible reasons for the “SIM 1 Not Allowed” issue. Then, we will tell you what you should do to get rid of this error on your device.
Note: Although we haven’t mentioned, this guide is also applicable to any Samsung Galaxy S20, and Samsung Galaxy S21 models (S20/S21 Plus, S20/S21 Fe, and S20/S21 Ultra)
Why do you get SIM 1 not allowed on Samsung S20 or S21?
SIM 1 not allowed error usually occurs due to the IMEI being blocked or when a carrier locks the SIM 2 slot on your Samsung S20/S21. However, configurations in the network settings, system bugs/glitches, and hardware failures all contribute to the SIM 1 not allowed error.
If you are not the first owner or the user of your Galaxy S20/S21, then there is a chance that the IMEI of your phone’s SIM 1 slot has been blocked by a carrier. If you ask why a carrier locks the IMEI number, then it can be due to overdue of payments, unauthorized activities, or even going against its policy (Like selling the phone to another person).
The second reason is applied if you purchased the device from a carrier (In the USA like Verizon, AT&T, Sprint, T-Mobile, etc.) These carriers usually lock one SIM slot to stop people from using another SIM card (a.k.a using another network) on their device. Since you cannot access the other SIM slot, you will be left with their network, thus forcing you to use their service. Which most people don’t like much.
If we talk about configuration issues, there can be accidental settings that you might have turned on (Like disabling the SIM slots) or turned off (Like the network recovery). Although you haven’t done anything to network and SIM card settings on your Galaxy S20/S21, software updates, and third-party apps can also cause to produce the SIM 1 not allowed error.
Lastly, hardware issues are not very rare for these two devices (S20/S21). It is because some users have brought their smartphones to the Samsung service center and the result was they claimed the warranty due to hardware issues with the SIM 1 slot.
So these are the reasons why you are getting SIM 1 not allowed error on your Samsung S20/S21. But don’t worry. Although you might feel this is a hard-to-solve problem by reading the reasons, it is not that hard to fix.
Let us show you how you can fix this problem. Keep reading…
How to fix SIM 1 not allowed on Samsung S20 & S21 easily
You can skip if there is any solution that you have already tried before. First, we will do some ground-level work to make the base to fix this problem. Then, we will tell you what you should do to make the SIM 1 slot work and get rid of SIM 1 not allowed error on your Galaxy S20/S21.
Fix 01: Reset network settings
There are still a number of users who got solved this problem by resetting the network setting on their smartphones. Therefore, it is work giving this solution a try.
Here is how to reset the network settings on your Samsung Galaxy S20/S21
- Open Settings
- Tap on General management
- Under general management, tap on Reset
- Then, Tap on Reset network settings
- Confirm and proceed to reset network settings
Once it is completed, power off the device. Then insert a SIM card into SIM 1 slot and power on your phone, and see if the solution works.
Fix 02: Remove, and change the SIM card in SIM 1 slot
Although we didn’t mention earlier, sometimes faulty SIM cards can also cause to SIM 1 Not Allowed issue. Therefore, use a paper clip or the SIM tool you got with your Galaxy S20/S21 and take the SIM tray out. Then, clean the surface of it and use a working SIM card and insert it into the SIM 1 slot and insert the SIM tray into the phone again. Then, power on the device.
If you still get the SIM 1 not allowed error even after doing that, then there is a problem with the IMEI of the SIM 1 slot, or the carrier has blocked the device from using the SIIM 1 slot.
Let’s see how you can fix those two problems and make the SIM 1 slot work again.
Fix 03: Check the IMEI status
Before you are going to unblock the IMEI on your Samsung S20/S21, you need to check the IMEI of the SIM 1 slot to make sure whether it is blocked or not. And here is how you can do that.
There is an online tool you can use to check the IMEI called IMEI.info. According to them, they have a large database that gets updated every day on the IMEI locking status and many more. However, to check the IMEI lock status, you have to pay a small fee (When we last checked the price, it was 3 USD per IMEI check). Considering how badly you want to figure this out, it is worth giving a try.
Note: We are not affiliated or working together with the IMEI.INFO website. Also, we do not guarantee or take any responsibility for the payments made to that website.
With that being said, here is how you can check if the IMEI of the SIM 1 slot of your Galaxy S20/S21 is locked.
- Go to the IMEI blacklist check – IMEI.info
- Type the IMEI number of the SIM 1 slot. You can get the IMEI number by dialing *#06#
- Tap/Click on the Check blacklist pro button
- Then you will get the payment screen, do the payment and verify the IMEI.
If you get something like this, it means the IMEI of the SIM 1 slot of your device is blocked by a carrier, you can also see which carrier has blocked the IMEI. You can use that information to contact them and get the IMEI unblocked.
Fix 04: Contact your carrier
If you purchased your smartphone from a carrier, then you can contact their customer support and ask them to check if your device’s SIM slot is blocked. If so, you can unblock the SIM slot from their end and use any SIM card in that slot to use without any problem.
Fix 05: Reach the Samsung service center
If none of the above solutions worked, then chances are high that there is a hardware failure on your Galaxy S20/S21.
To check this, without doing anything like resetting the device, clearing cache, etc, go directly to the nearest Samsung service center. Then let the experts take care of the issue.
Even though the SIM 1 not allowed error can be caused by various problems, not all of those are on your hand to solve. That is why we gave all the solutions to you, to try and get the SIM 1 slot working.
If you have any questions regarding this guide or need help, leave a comment below. So we can help you from there.
Have a nice day!