I can no longer connect to the Target CPU

Sometimes it can happen that the Target CPU ends up in a unrecoverable state after the debug session was established and operational. Neither performing Download or CPU Reset command regains winIDEA control over the Target CPU.

Possible solution:

Try to restart the whole setup via Power Off/On cycle. 

Considering the system is powered, perform the power cycle in the following order:

1. Turn off the target.
2. Turn off the BlueBox.
3. Wait a second.
4. Turn on the BlueBox.
5. Turn on the target.
6. Execute CPU Reset command (Debug / Run Control / CPU Reset).