To check the unlocking attempts left on your Sony phone, do the following:
1. Remove the SIM card from the phone and Switch On.
2. Dial *#*#7378423#*#* as a phone number.
3. Select Service info.
4. Select SimLock.
5. Check the number beside Network, which indicates how many attempts you have to unlock the phone. If it says ‘6’ it means you have six attempts left; if it says ‘0’ means it is hard locked and cannot be unlocked.
You can check the device IMEI by just dialing *#06#.
To unlock the Sony phone, insert any unacceptable SIM card and switch On. It will prompt for SIM network unlock PIN.
Enter the unlock code which is provided by mysimunlock.net. Tap “Unlock”.
Note: If no attempts will be left to enter on the phone, then also Sony phones prompt to enter the unlock code. But, it will never accept the NCK code and can not be unlocked.