N910T Downgraded To 5.1.1 Unlock Error

Ok, I rooted this device.... downgrade from 6.0.1 to 5.1.1 and try to unlock but still end up with Error (02). @blang said new security so I did downgrade!

Galaxy Note 4
SM-N910T
Android Security Patch: 2015-11-01
Baseband: N910TUVU2DOK2
Build: Maximum_OvrDriVE

Still don't get it!