Adding new key to P2 S60

[TijmenR]

Hi, im trying to add a new blank key with blank ID48 chip to my car, the remote is working now but when I am trying to add the ignition key in the "Add Key Wizard" it takes me to the page "Add / Pair key wizard with these instructions:

1: Prepare a blank (deleted key)
2: Press the "start adding key" button
3: When prompted, insert the key into the shaft
4: Wait until the pairing is complete

But once I press the start adding key button it loads for a while, restarts the car and then gives me this message "adding key failed (the key is probably already programmed in another car)", But it did not even prompt me to put in the key.

I've tried doing it with the key inserted, not inserted, inserted on position 0, position 2, but it keeps giving the error, the remote is working but when trying to start the car its giving me the immobilization message.