It is looking for either the Reset Protection recovery key or the account that it was signed into to enable reset protection before it was reset. Without internet the second item will not disable it. Like stated above get it on the interet. Or login to the Microsoft account used to enable the reset protection on that phone, and find the device and imei and remove the phone from your account. Make sure it is the exact same device you are talking about imei name model etc. When removing it from your devices list it will prompt you to save the reset protection key. That key can disable the reset protection without an internet connection.
https://support.microsoft.com/en-us/...otect-my-phone