Htc U ultra S-off not done

htc u ultra, oem blocked, does not want to make s-off, any solution, unlock bootloder can not make an error

1. Checking phone connectivity...
... (bootloader) cid: 11111111
OKAY
Execution time is 15(s)
Reading MEID information
... (bootloader) meid:
OKAY
Execution time is 10(ms)
Reading IMEI1 information
... (bootloader) imei: 3551660804.....
OKAY
Execution time is 10(ms)
Reading IMEI2 information
... (bootloader) imei2:
OKAY
Execution time is 9(ms)
Reading secure flag information
... (bootloader) Device security level S-ON, reboot count 0
OKAY
Execution time is 2(ms)
Reading serial number information
... (bootloader) Device Serial No. is FA737170....
OKAY
Execution time is 10(ms)
Read information completed.
Phone connection confirmed!
HTC KEY CARD VERSION: 7
2. Checking Server connectivity...
Server connection confirmed!
3. Checking PowerAdapter connectivity...
Process started
PowerAdapter connected, processing request to adapter...
Starting operation...
Sending oem writesecureflag 0
... (bootloader) HTC KEY CARD VERSION: 7
Building connection
Initiating communication
Building connection
Data exchange sequence.
Requesting information from server
Request sent, waiting 3 seconds for reply...
Processing...
Data exchange completed
Data exchange sequence.....
(bootloader) Write security level S-ON
OKAY
Execution time is 13(s)
Operation completed!
Releasing adapter.
Request completed