Update 11:35 CEST: The issue is still apparent for some users. The reason is that the DNS change has to propagate to all DNS servers for the issue to be fully solved. We have made all the necessary changes on our end so for now all we can do is wait for the changes to spread. We're monitoring the changes and will update this incident as needed.
This morning we had an issue with DNS for the domain ubivox.com. The issue has been solved but for a while the domain would have been inaccessible for some of our clients.