We're investigating a problem with calls on the A and C VoIP server.
We have identified that the fault is being caused by VoIP software crashing by an obscure call set up configuration. Another update is due shortly.
We've pinned this down to a the actual Number that is triggering this problem, and are in the process of changing the config.
The config has been changed, but we are still investigating the underlying problem.
Service had been stable this afternoon, we're still investigating the root cause.