How to fix Galaxy S9 Plus invalid SIM card error

Hello Android fans! This post will answer another common problem for the Galaxy S9 Plus: Invalid SIM card error. We provide all the software troubleshooting steps that you can do on your end. Remember, other factors may affect the network performance of your phone so if nothing changes after exhausting all software troubleshooting, you should contact Samsung or your carrier for further support.

Problem: Galaxy S9 Plus invalid SIM card error

I have two Galaxy S9+ and one has had the SIM card replaced and is now giving an error for an “invalid sim card” again. I’ve bad multiple issues with that specific device and I need a fix or a brand new, not refurbished, phone.

Solution: “Invalid sim card” error can be sign of one of the following:

SIM card is not active
SIM card is defective
account (with your carrier is problematic)
SIM tray is damaged
phone is damaged
network issue
bad app
software glitch

To troubleshoot “invalid sim card” error, you need to do a series of logical steps.

Force reboot

Sometimes, this simple procedure can fix bugs that developed after the system has run for a long time. By manually forcing your S9 Plus to reboot, you’re basically simulating a battery pull, which, in older mobiles with removable battery packs, was an effective way to refresh the system. If you haven’t tried this one yet, here are the steps that you can do:

Press and hold the Power + Volume Down buttons for approximately 10 seconds or until the device power cycles. Allow several seconds for the Maintenance Boot Mode screen to appear.
From the Maintenance Boot Mode screen, select Normal Boot. You can use the volume buttons to cycle through the available options and the lower left button (below the volume buttons) to select. Wait for up to 90 seconds for the reset to complete.

Reseat the SIM

Invalid SIM card error may sometimes be caused by a SIM card or network bug. Try to reseat or disconnect the SIM card from the phone and see what happens. Here’s what you need to do:

Make sure to turn off the phone first.
Remove the SIM card.
Wait for at least 30 seconds.
Re-insert the SIM card into the phone. Be sure it’s positioned correctly.
Turn the phone back on and check for the problem.

Check for bad apps

Some apps may cause problems to the system. To check if there’s a downloaded app that’s causing this problem, restart your phone to safe mode and observe it. Here’s how you do that:

Turn the device off.
Press and hold the Power key past the model name screen.
When “SAMSUNG” appears on the screen, release the Power key.
Immediately after releasing the Power key, press and hold the Volume down key.
Continue to hold the Volume down key until the device finishes restarting.
Safe mode will display in the bottom left corner of the screen.
Release the Volume down key when you see Safe Mode.
Check for the problem.

While on safe mode, your Galaxy S9 Plus will only allow third party apps to work. All downloaded apps will be blocked and won’t be able to run. Make sure to let your device run in safe mode for at least 24 hours so you’ll notice any difference. If the phone works normally and “Invalid sim card” error won’t show, you have an app problem. In order to identify which of your apps is causing the problem, you need to use the method of elimination. Here’s how to do that:

Boot to safe mode.
Check for the problem.
Once you’ve confirmed that a third party app is to blame, you can start uninstalling apps individually. We suggest that you begin with the most recent ones you added.
After you uninstall an app, restart the phone to normal mode and check for the problem.
If your S9 Plus is still problematic, repeat steps 1-4.

Reset network settings

Another troubleshooting step that you must do in this situation is to clear the phone’s network settings. This is often effective in fixing network troubles. If the invalid SIM card error is being caused by incorrect network configuration, this might help.

To reset your phone’s network settings:

From the Home screen, swipe up on an empty spot to open the Apps tray.
Tap General Management > Reset settings.
Tap Reset settings.
If you have set up a PIN, enter it.
Tap Reset settings. Once complete a confirmation window will appear.

Restore all software settings to defaults

Factory reset is a drastic solution for many issues including network-related ones. If all the suggested steps above has not helped so far, consider wiping your phone to see if there’s a difference. If a software bug is causing the error to pop up, resetting your phone to its defaults may work.

To factory reset your Galaxy S9 PLus:

Create a backup of your data.
Turn off the device.
Press and hold the Volume Up key and the Bixby key, then press and hold the Power key.
When the green Android logo displays, release all keys (‘Installing system update’ will show for about 30 – 60 seconds before showing the Android system recovery menu options).
Press the Volume down key several times to highlight ‘wipe data / factory reset’.
Press Power button to select.
Press the Volume down key until ‘Yes — delete all user data’ is highlighted.
Press Power button to select and start the master reset.
When the master reset is complete, ‘Reboot system now’ is highlighted.
Press the Power key to restart the device.

Contact your network operator

Invalid SIM card error can also be an indication of a possible issue with your account. At this point, make sure to talk to your carrier about it so they can troubleshoot the problem and check if there’s any network or account problem that may have effected your device or SIM card.

Hardware issue

If there’s no change after reseting the phone to defaults, you can assume that the reason for your problem is on the hardware side. Contact Samsung or your carrier to have your phone repaired or replaced.

When it comes to replacement programs, Samsung or carriers almost always provides refurbished units. Talk to them to get accurate information about this.