I can't start my Samsung Galaxy Z Flip4 Android 12.0
Cause 4 of 6: Your phone is locked to another operator
If your phone is SIM locked to another operator and you try to use a Lebara SIM, the screen will tell that your SIM is invalid.
Solution: Before you can use a Lebara SIM, you need to unlock your phone using an unlock code. To get the unlock code, contact the operator that locked your phone.