Anthony from DNSimple here. I'll pass along what I know so far: some of nic.io's name servers appear to be no longer delegating .io domains out to authoritative name servers. Some of their name servers are still delegating properly, but some are not.
This issue also affects .sh and .ac TLDs I believe since they are the same registry. If I find out anything new I'll post on Twitter in the @dnsimple account and here.
ooo, you do 301 redirects, I'll be over shortly...
To explain why that's useful, we have three domains, draw.io (mutter), diagramly.com and diagram.ly that all map to the same thing. The actual site runs on a Google App Engine appspot domain. On GAE, you have to buy a Google Apps for Business account to map a domain to an GAE appspot domain.
We have three Apps accounts because of this. We're not happy to do the 301 on a physical server, that loses the scalability advantage of GAE. This has always needed to be done at the DNS level ( I know it's not truely a DNS feature, but I'm assuming the scaling of the redirects at someone who does it as a service is better than mine ). This is the first time I've seen this service. That's all...
This issue also affects .sh and .ac TLDs I believe since they are the same registry. If I find out anything new I'll post on Twitter in the @dnsimple account and here.