ESP32 azure Iot Kit stopped recognized by usb COM port

[chrispal]

Hello everyone,
I was working without any problems the last months with my ESP32. Suddenly, my device is not regognized by serial COM port of my pc. When i plug it in,looking at the device manager, it is showing for a second and then the connection is lost.
I didnt change my USB cable and the usb-serial CP210X driver is also installed. Everything stopped working after a firmware upload to the chip.I dont thing that i had something dangerous to that firmware. What could went wrong?
Thank you

[chrispal]

Update:
When i connect another same device, it is normally detectable in the device manager. So i guess something is wrong with the device it self? Can this be something that i provoked?