Arduino Uno and ISP programming on AS7

Goodmorning everyone,
I have an Arduino One who does not want to be programmed via USB.
Then I connected to Atmel-Ice via the ISP and started AS7
Checking the FUSE I activated the DWEN to do debugWIRE but after what I could no longer access the microprocessor.
Now I have always an error like this:

Timestamp: 01/06/2017 09: 31: 48,554
Severity: ERROR
ComponentId: 20100
StatusCode: 1
ModuleName: TCF (TCF command: Device: startSession failed.)

Failed to enter programming mode. ispEnterProgMode: Error status received: Got 0xc0, expected 0x00 (Command has failed to execute on the tool)

How can I recover communication with the micro? :o

Thank you,

Simone

Is the IPS frequency correct ?

Do you power the arduino when you try to connect to it ?