sm g920f

trying to unlock but cant , the following keeps coming up,
iv build number and have usb debug set
any ideas?
trying Operation: Unlock
Selected model: SM-G920F
Software version: 27.1

Searching Samsung modem… detected COM54
Reading phone info… ok
Model: SM-G920F
AP version: G920FXXS4DPIR
CSC version: G920FVFG4DPHB
CP version: G920FXXS4DPIF
Product code: SM-G920FZKAVOD
Phone SN: RF8H51XMW4W
Unique number: 0416047427242F02
Reading IMEI… ok
IMEI: 000000000000000 (SIGN: OK)
Reading data from phone… error (0)
Try downgrade modem if possible

Done with Samsung Tool PRO v.27.1to unlock the sm g920f with z3xbox, the following keeps happening