ESP32 not responding to COAP requests with services

Hi, I have loaded my ESP32 with a COAP server script found at:

The ESP32 demo script is for a COAP server with a single service named "light"

And in my Windows10 Chrome setup I loaded an Extention that talks COAP and should be able to comunicate with the above COAP server.
The Chrome Extention can be found at:

I used Chrome with the Copper extention to sucessfully access a sandbox COAP server at:
Clicking Discovery brings all services available at, tens of demo services.

So Chrome's COAP capabilities are demonstrated to be working ok.

When I point Chrome( via Copper Extention) to the local IP address on my ESP32 loaded with the COAP Server (set as above) it works but does not show the "light" service that is running in it.

If I click on Discovery (something that worked on it shows a message 4.04 Not Found.
The discovery scan should be able to find all services provided by the COAP server running on my ESP32 but finds no services at all.

Using Wireshark I checked that the 4.04 Not Found is a response comming from my ESP32.

Any assistance will be welcome

Thanks in advance.
Paulo Borges