Two People Fine, Three Static City

[StuartR]

My trio is trying without success to put together a JamKazam session. When any two of us are in the session, everything is perfect, no latency and crystal clear audio. However, whenever the third player enters, all static hell breaks loose. Everything becomes totally unintelligible, just white noise static. 

We’ve switched the player who is out of the session and it makes no difference, any two are fine.  It’s only when the third joins that the problem appears.

Any ideas??

TIA

what Network Route setting do you all have set - Prefer lowest latency path OR Prefer peer to peer path?