VoIP - Unable to make or receive calls.

A number of processes had failed to restart in the correct order due to system load. An appropriate delay has been added to prevent re-occurence.
Normal service was resumed at 11:47.
Our apologies to those affected.

Calls are now flowing as expected, although investigation into the cause is ongoing.
Our apologies for the inconvenience

We are investigating inability to make/receive calls on a number of our VoIP platforms. This has been raised as a Tier 1 incident to the provider as a precaution while we continue internal investigation.