Sm-n920w8 [can’t unlock]

Hi , trying to unlock a SM-N920W8. I have the latest octopus version. 2.1.7 and the phone is rooted but everytime i try to unlock it, it does it successfully but it erases the imei of the phone and the imei becomes Null/Null. If I try to read codes, i get the error "Can’t find code". Is there any way to unlock this phone?