The DNS issue has now been resolved however due to the nature of DNS it could take upto 48 hours for the DNS to fully update.
Posted May 05, 2017 - 21:29 BST
Identified
We have an issue with the domain used for SIP services. This has been traced to a DNS problem which is being worked on. In the meantime your endpoint may have issues resolving the IP. We apologise for an inconvenience