MS500 flashing failed please how to solve?

I have been trying to flash this LG MS500 but there is no success,
please how will I solve it?

Flashing log below;

Welcome to Octoplus/Octopus Box LG Software version 2.1.7
Checking data…OK
Platform: LG Qualcomm
Selected port: COM28
Selected model: MS500
Reading info…
Model ID: LGMS500-00-MS50012b-TMO-US-MAR-24-20140
Android version:
Battery level: 50%
Mode: Emergency
Model ID: BS/LGMS500/105435
SW version: LGMS500AT-02-V12b-310-260-MAR-24-2014+0
Product ID: CT65S131212003711
IMEI: 013758-00-121260-2
Opening "LGMS500AT-02-V12b-310-260-MAR-24-2014+0.oct"…OK
Initializing flash…OK
Testing connection…OK
Writing PrimaryGPT…Failed!
Error code: ZXLCALSZXD