Got a strange problem that has only begun to manifest itself since we started using a host running FreeSWITCH 1.2.24. We were previously using a host running 1.2.13. Both hosts are hosted at Hetzner. I'm not 100% sure that the relevant parts of configuration haven't changed, although I don't think they have. The phones are on a NATted LAN connected via ADSL to the Internet. The problem is that, despite showing up as registered (and continuing to re-register), the phones can get into a state where they don't respond to inbound INVITEs. Other brands of phone (eg. Linksys and Yealink) appear NOT to suffer from this problem. The thing that baffles me is that this appears to be repeatable, but differs between the hosts. What parts of FS config should I be looking at for differences?