AutoDiscovery example does not works

Part I:
I tried, yesterday, on two Macintosh an old project (around 15 years old) that use AutoDiscovery and who worked then (on Windows <–> Macintosh).

As strange as it seems, I was able to send messages from the older Macintosh/MacOS [2009/Mavericks ?] to my MacBook Pro from nearly 4 years with El Capitan, but I was not able to send anything from the younger MacBook Pro.

Nota: I can send messages to the Group (no one receive them) or to Private.

Worst: I do not have any value other than 0 from this code:

niCount = System.NetworkInterfaceCount-1

After some search, I added a brand new PopupMenu and put code there to populate it accordingly of the LR. On the MacBook Pro, there is 0 NetworkInterface.
On the WIndows 1803 laptop, they are 3 (0-2).
I have an AutoDiscovery Properties window that report NetworkInterface as Nil.

So, I started to make a search and found an example in the Example folder. Read below.

Part II:

does not uses System.NetworkInterface(Int) nor System.NetworkInterfaceCount, etc.

Yes, I compiled that > 15 years old example, copy one to my Windows 10 1803 laptop and fire the MacOS version (El Capitan): nothing.

Then, I ran Xojo 2018r1.1 and run the project there: nothing…

Then, I checked code and do not understand. So I made some code searches and do not find anything related (code) to AutoDiscovery…

The sent messages appears nowhere. I do not even understand what the numerical value is meant to…

If someone have used that technology or example can try to help… TIA.