No No it's not your Forgotten Security code restriction code means Network unlock code, I will make it clear ...
If your Nokia mobile phone displays Phone Restricted with an Undo option and selecting Undo results in an Enter Restriction Code error, your Nokia mobile phone is Network Locked. This means your Nokia mobile phone has been restricted for use on one specific network and a Restriction Code or Unlock Code must be entered before the phone can be used with alternative networks.
You need to specify the Current Network and Country it locked now,you can get the code from here Mobileunlocksolutions.com
and Unlock it from Network Restriction lock.