Our own tests show that .io domains are working again, but we've not received any confirmation from upstream providers yet. We continue to monitor the situation closely.
Posted Oct 28, 2016 - 12:27 UTC
Update
The .io registry has confirmed that they know about the issue and are working on a fix.
Posted Oct 28, 2016 - 09:26 UTC
Update
Media files (uploaded images) of live sites are also affected, since they are served from a .io domain.
Posted Oct 28, 2016 - 09:15 UTC
Identified
The top level domain name provider for .io domains is having intermittent issues resolving some domains.
This is causing the automatically generated domain names like mysite.us.aldryn.io to not always work. Live sites with a custom domain are not affected as long as they are not using a .io domain.
details:
https://news.ycombinator.com/item?id=12813065 and http://dnsimplestatus.com/incidents/7hnh1jttbj6z