IPv6 for SIP unavailable
It looks like Jami doesn't support IPv6, neither does Jami listen on IPv6 when it is started up or does it allow calling an IPv6 host (truncates the address then says Bad URI).
This is pretty sad knowing that SIP will usually perform better in IPv6 since hosts can have a public address of their own and establish direct connections without relying on clumsy NAT bypass techniques and port redirections.