Help FRP Z971

Trying to remove FRP always error. Tried selecting Z835 and ZTE Spark from list:

Code:

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SigmaKey v.2.27.18
351936139 Sigma dongle 2.27, Initializing...OK
Pack 1: Activated
Pack 2: Activated
Pack 3: Activated
--------- 2018-05-02 17:08:11 ---------
SigmaKey 2.27.18 Qcom: Remove FRP / Huawei ID
Cancelled
--------- 2018-05-02 17:09:07 ---------
SigmaKey 2.27.18 Qcom: Remove FRP / Huawei ID
ZTE Handset Diagnostic Interface (COM386), Provider: ZTE Corporation, Driver ver.: 5.2104.1.2, Date: 3/16/2014, USB\VID_19D2&PID_0500&REV_0318&MI_00
Phone model: ZTE Maven 3 Z835
Version: P817A22V1.0.0B20,
Firmware: MPSS.JO.2.0.c1-00179-8937_GENNS_PACK-1.95826.1.96615.1
Date: Jul 24 2017 19:54:14, Apr 26 2017 06:00:00, 8937.gen
Sending boot...Failed
--------- 2018-05-02 17:10:22 ---------
SigmaKey 2.27.18 Qcom: Remove FRP / Huawei ID
ZTE Handset Diagnostic Interface (COM386), Provider: ZTE Corporation, Driver ver.: 5.2104.1.2, Date: 3/16/2014, USB\VID_19D2&PID_0500&REV_0318&MI_00
Phone model: ZTE Maven 3 Z835
Version: P817A22V1.0.0B20,
Firmware: MPSS.JO.2.0.c1-00179-8937_GENNS_PACK-1.95826.1.96615.1
Date: Jul 24 2017 19:54:14, Apr 26 2017 06:00:00, 8937.gen
Sending boot...Failed
--------- 2018-05-02 17:11:17 ---------
SigmaKey 2.27.18 Qcom: Remove FRP / Huawei ID
ZTE Handset Diagnostic Interface (COM386), Provider: ZTE Corporation, Driver ver.: 5.2104.1.2, Date: 3/16/2014, USB\VID_19D2&PID_0500&REV_0318&MI_00
Phone model: ZTE Spark R84 [?]
Version: P817A22V1.0.0B20,
Firmware: MPSS.JO.2.0.c1-00179-8937_GENNS_PACK-1.95826.1.96615.1
Date: Jul 24 2017 19:54:14, Apr 26 2017 06:00:00, 8937.gen
Sending boot...Failed

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Please help