Hello Keith,
We did replace one of our severs recently, but it wasn't a server in Australia. Still, I recommend that you reset ('flush') the DNS resolver cache on your Viewer computer just in case.
In order to flush DNS please execute this command in Windows CMD:
ipconfig /flushdns
If that doesn't help try to reset it also on of the Host computers and test connectivity. If that doesn't help please let us know.
Thanks.