So when I ran the new Jami, it bumbled along and finally announced (in log output to the terminal, only, in yellow) that its PUPnP / NAT-PMP had failed after 3 tries. Earlier it said, in red: “Address lookup for c739b288f587637af47eaefcd47edb65103b858d failed with code=0”, but then, in yellow, “[Account 5fcd6682a05edb1b] connected”.
(Most of what seem like, usually, error messages are in yellow, and wholly unreadable without copying to somewhere else.)
When I tried to register a user name, that failed too, as reported in the dialog box, “Something went wrong”. (Period.) The terminal reports (in yellow) just "Name registration ended. Account: “5fcd6682a05edb1b” status: 2 name: “xxx@yyyyyyy.zzz”.
So, I don’t know how to get a user name registered.
(For completeness… this is running in a VM that is NATted. I don’t have other network problems, e.g. Google Meet, Signal, and Zoom negotiate voice connections without apparent difficulty.)