s6 reactivation lock problem

Collecting information. Be patient! Do NOT disconnect the phone!
Model: SM-G920F
Sales Code: BTU
Country Code: UK & IRE
Timezone: Europe/London
Android Version: 7.0 [NRD90M] [SDK 24]
Build Date: Wed Jun 20 16:33:06 KST 2018
PDA Version: G920FXXU6ERF5 [june 2018, rev5]
CSC Version: G920FBTU6ERG1 [july 2018, rev1]
Board Platform: EXYNOS5
Serial Number: R58H63YJTBP
Battery Status: 3.83V (32%)
Network Type: GSM
SIM Status: NOT_READY
Knox Version: v30
Warranty Bit: 0
Security Patch: 2018-06-01
Data Encryption State: unencrypted
Resetting R/L by engineering boot-based method.
Processing...
Processing. Be patient! Do NOT disconnect the phone!
After the reboot, you can install a stock firmware if the boot process get stuck.
Checking custom root image...
Present.
Rooting by custom image-based root method...
Flashing firmware...
Switching to download mode.
Waiting for download mode.
Connecting.
SBL Info: Model: SM-G920F, Region: EUR, Provider: OPEN, PDA: G920FXXU6ERF5
Reading PIT from phone.
Flashing boot.img
Firmware flash failed.
Finished at local time: [08.24.18 10:44:34]
WorkID: 42924086
any solution
phone is rooted any way