SM-A520F Reading SN... error (1) Operation: Unlock

HELP
Operation: Unlock
Selected model: SM-A520F
Software version: 32.4

Searching Samsung modem... detected COM23
Reading phone info...
Model: SM-A520F
AP version: A520FXXU4BRC4
CSC version: A520FOXE4BRAH
CP version: A520FXXU4BRC1
Product code: SER
Phone SN: R58JA4GBPGD
IMEI: 353627096356020
Unique number: CBJ00E1E7EE26A4
Reading IMEI... OK
IMEI: 353627096356020
Reading SN... error (1)

Done with Samsung Tool PRO v.32.4