Mbed Studio can't debug

Mbed OS
7

Greetings!
The great news is Mbed Studio 0.8.0 supports debugging NUCLEO-F767ZI.
Regretfully though, all I could get is this message:

Selected port 50000 for debugging
0000496:INFO:board:Target type is stm32f767zi
0000501:INFO:coresight_target:Asserting reset prior to connect
0000504:INFO:dap:DP IDR = 0x5ba02477 (v2 rev5)
0000513:INFO:ap:AP#0 IDR = 0x74770001 (AHB-AP var0 rev7)
0000529:INFO:rom_table:AP#0 ROM table #0 @ 0xe00fd000 (designer=020 part=451)
0000534:INFO:rom_table:[0]
0000534:INFO:rom_table:  AP#0 ROM table #1 @ 0xe00fe000 (designer=43b part=4c8)
0000539:INFO:rom_table:  [0]
0000540:INFO:rom_table:    AP#0 ROM table #2 @ 0xe00ff000 (designer=43b part=4c7)
0000554:ERROR:ap:Transfer error while reading AP#0 ROM table: SWD/JTAG Transfer Fault @ 0xe000efbc-0xe000f043
0000579:CRITICAL:__main__:No cores were discovered!
Traceback (most recent call last):
  File "c:\Users\User1\AppData\Local\Mbed Studio\mbed-studio-tools\python\lib\site-packages\pyocd\__main__.py", line 343, in run
    self._COMMANDS[self._args.cmd](self)
  File "c:\Users\User1\AppData\Local\Mbed Studio\mbed-studio-tools\python\lib\site-packages\pyocd\__main__.py", line 571, in do_gdbserver
    with session:
  File "c:\Users\User1\AppData\Local\Mbed Studio\mbed-studio-tools\python\lib\site-packages\pyocd\core\session.py", line 287, in __enter__
    self.open()
  File "c:\Users\User1\AppData\Local\Mbed Studio\mbed-studio-tools\python\lib\site-packages\pyocd\core\session.py", line 367, in open
    self._board.init()
  File "c:\Users\User1\AppData\Local\Mbed Studio\mbed-studio-tools\python\lib\site-packages\pyocd\board\board.py", line 83, in init
    self.target.init()
  File "c:\Users\User1\AppData\Local\Mbed Studio\mbed-studio-tools\python\lib\site-packages\pyocd\core\coresight_target.py", line 164, in init
    seq.invoke()
  File "c:\Users\User1\AppData\Local\Mbed Studio\mbed-studio-tools\python\lib\site-packages\pyocd\utility\sequencer.py", line 208, in invoke
    resultSequence = call()
  File "c:\Users\User1\AppData\Local\Mbed Studio\mbed-studio-tools\python\lib\site-packages\pyocd\core\coresight_target.py", line 298, in check_for_cores
    raise exceptions.DebugError("No cores were discovered!")
DebugError: No cores were discovered!
"GDB server stopped unexpectedly with exit code 1"

Any idea what could go wrong?
I’d appreciate any suggestion,
George.