General Network Advice

[penzo.livio]

... since the beginning I always get a No audio from partners...

And what does your Solo Session report? Does it work for you? I think that if Solo Session works for you, then the "no audio from partners" is on their end. Last I successfully tried (several weeks ago now), it all worked for me fine. Then, with no configuration changes, I tried again a week later with my brother and one other. The one other and I chatted just fine, but my brother could hear us but not transmit to us. We believe the issue is somehow on his end, but he's not been able to crack it yet.

Good luck -- write back with good findings!

I was trying to connect to a friend which is ok as he is able to join properly to any free Jamkazam session. The problems seems then on my side. The system message states the problem is on the router so I contacted the ISP managing the router and let him make the checks/changes required by the basic configuration I found somewhere on the forum (latency below 20 ms, UPNP enabled, public router,  udpport 12000-12001, of course LAN not wifi, etc.) but it did not help at all. 
Now I can try this Solo session, but could you please help me describing on how to proceed ? Livio from lockdown Italy