[EE] Lenze inverter

Hi all.

I'm facing a burned Lenze E82EV751-2B and I hope to discover what causes
this failure.
"The notor disyuntor key was down", "The Lenze pcb is toasted", accordingly
to the
engineer description.
I didn't see it yet. All this things point to the motor, but may be someone
unpluged the mains while the machine was running... I don't know.

It is interesting because the Lenze has a very complex
system to defend it self against that:
• Short-circuit-resistant, protected against earth faults
  during operation
• Configurable current limiting, warnings and error
  messages in the event of overcurrents
• Protected against overvoltages and undervoltages
• Warnings and error messages in the event of
  overtemperatures on the frequency inverter
• Input for PTC or thermal contact and I2t monitoring for
  motor protection
• Motor phase failure detection
• Integrated brake transistor (up to 11 kW)
• Integrated RFI filters to EN55011 class A or B
  (device-dependent)

Any sugesstion in how to debug this, it will be very appreciated.
I don't want to just replace the inverter.

Regards,