Samsung G950U1 Mode Can't Download (bksecapp)

Same problem: Phone Samsung G950U1 Mode Can't Download (bksecapp)
Telephone not flashed - when flashing to the same firmware version, which was the error MDM Mode Can not Download (bksecapp)
Not Startet Android and recovery only download mode
Last firmware:
Detected phone model: SM-G950U1
Firmware compiled date: Wed Apr 11 18:07:00 KST 2018
PDA version: G950U1UEU3CRD4
CSC version: G950U1OYM3CRD4
SW version: G950U1UEU3CRD4
Phone SN: R28J81ZMX9B
Android version: 8.0.0 (R16NW)
Sales code: XAA
Country: USA
HW platform: msm8998
HW Chip: MSM8998
HW Modem: MSM8998