Poweradapter htc u ultra problem s-off problem

Hello,
i have htc u ultra
and it has android 8.0 version now
i cant do s-off with power adapter

1. Checking phone connectivity...
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...
Waiting 3 seconds more...
Processing...
Data exchange completed
Data exchange sequence.....
(bootloader) Write security level S-ON
OKAY
Execution time is 9(s)
Operation completed!
Releasing adapter.
Request completed