I can no longer connect to the Target CPU

Sometimes the Target CPU can end up in an unrecoverable state after the debug session is established and operational. Neither performing the Download or Reset command regains winIDEA control over the Target CPU.

Possible solution

Try to restart the whole setup via a 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 | Reset).