CSR generation starting fail on MKR1000

[Iolistic]

Hi,

I'm using the MKR1000 board, and trying to generate a CSR with the sketch example ECCX08CSR
the code stop at this condition:

if (!ECCX08CSR.begin(slot.toInt(), generateNewKey.startsWith("Y")) {
  Serial.println("Error starting CSR generation!");
  while (1);"

I locked the chip and get the SerialNumber when starting, it seems to work properly until the CSR genearation. i tried to bypass the condition, the CSR is empty.
How can i troubleshoot this ?
Thanks for help!