samsung g3815 flash error

hello great team i need help with g3815 when i want to flash its show me these error

[Firmware update started]
Selected model: SM-G3815

Extracting firmware...
Unzipping firmware: G3815ZHUAMJ6_G3815ZZHAMJ6_G3815ZHUAMJ6_HOME.tar.md 5.

Processing firmware...

Flashing firmware...
Waiting for download mode.
Connecting.
Firmware flash failed.
Finished at local time: [06.10.18 01:47:15]
WorkID: 39089803
and on phone screen on download mode
its say write protection Enable
and phone is stuck on logo