How to flash Encrypted Mobiles

How to flash such phones which has encrypted userdata
as while flashing its getting error, please refer to below logs...phone is getting restart after showing logo

Operation : Read Information
Checking for existing devices...Not Found
Turn Off phone, hold Vol UP + Vol DOWN and insert USB cable.
Some phones may need Special Boot Cable or TestPoint for EDL mode.
Found Port : Qualcomm HS-USB QDLoader 9008 (COM10)
Driver Info : Qualcomm Incorporated, qcusbser.sys, 2.1.0.5
Connecting to phone...OK
Waiting for response...OK
Init Handshake Sequence...OK
Hardware ID : E1600500 [8917] 00000000
OPK_DATA : 30315EBED1DD09CEAAE927CAE0EE967076BC178CA33718DB4F FF8F02A0E7FAD2
Initializing Protocol...OK
Using Auto Loader Selection [1]
Preparing Loader...Done
Sending Loader [8917_001]...Done
Executing Loader...OK
Detecting Chip Type...OK
Hardware : 8917, eMMC, 16 GB
LU Count : 1 [0x01D1F000]
WARNING! High Speed Driver is not installed.
Please install driver from QcFire\Drivers folder using Device Manager.
Payload Info : In: 65536 [4096], Out: 1048576, Sector Size: 512
Reading Partition Table...OK
Reading Device Information...OK
Device : vivo vivo PD1628F_EX [msm8937]
Software : MMB29M release-keys, eng.compiler.20181008.154817 [Mon Oct 8 15:54:58 CST 2018]
Android Ver. : 6.0.1
Patch Level : 2018-08-01
USERDATA : Encrypted
You can use DISABLE LOCKS to Disable Pin/Pattern/Password WITHOUT Data Loss.
Operation Finished.
QcFire Ver. 3.9




Operation : Flash
Checking for existing devices...Not Found
Turn Off phone, hold Vol UP + Vol DOWN and insert USB cable.
Some phones may need Special Boot Cable or TestPoint for EDL mode.
Found Port : Qualcomm HS-USB QDLoader 9008 (COM10)
Driver Info : Qualcomm Incorporated, qcusbser.sys, 2.1.0.5
Connecting to phone...OK
Waiting for response...OK
Init Handshake Sequence...OK
Hardware ID : E1600500 [8917] 00000000
OPK_DATA : 30315EBED1DD09CEAAE927CAE0EE967076BC178CA33718DB4F FF8F02A0E7FAD2
Initializing Protocol...OK
Using Auto Loader Selection [1]
Preparing Loader...Done
Sending Loader [8917_001]...Done
Executing Loader...OK
Detecting Chip Type...OK
Hardware : 8917, eMMC, 16 GB
LU Count : 1 [0x01D1F000]
WARNING! High Speed Driver is not installed.
Please install driver from QcFire\Drivers folder using Device Manager.
Payload Info : In: 65536 [4096], Out: 1048576, Sector Size: 512
Writing [NON-HLOS.bin] -> [modem] ...Failed
Operation Finished.
QcFire Ver. 3.9