LG D821 cant flash

i have problem with LG D821,when i try recovery mode, i see android and olways restart.
try flash

Checking data…OK
Platform: LG Qualcomm
Selected port: COM1
Selected model: D821
Reading info…OK
Mode: Fastboot
Model ID: hammerhead D821 16GB
Device serial number: 04adee480024661e
Hardware: rev_11
Bootloader lock state: unlocked
Opening "LGD821AT-00-V10b-NXS-OCT-31-2013-KRT16M-USER-16G+
Initializing flash…Failed!
Performed by 2.1.9 software version.

maybe you can help me?
thank you in advance