root problem A520F

Rooting by custom image-based root method...
Flashing firmware...
Switching to download mode.
Waiting for download mode.
Connecting.
SBL Info: Model: SM-A520F, Region: EUR, Provider: OPEN, PDA: A520FXXU7CRL8
Reading PIT from phone.
Flashing boot.img
Restarting phone.
Unable to restart.
Restarting failed.
Finished at local time: [02.19.19 17:56:46]
WorkID: 52975068

need help please