Error 1016 when accessing sites with same DNS provider, through a single Cloudflare node

Beginning last night, clients located in and around Calgary, Alberta, Canada began receiving Cloudflare 1016 errors when trying to access sites that were set up with Cloudflare’s CNAME setup. Not just any CF sites, though. The common thing that the errored sites shared was that they had Network Solutions as their DNS host. Other CF sites that were configured via CNAME setup, but did not use Network Solutions, were reachable. This problem was observed when clients used multiple ISPs, including Shaw, Telus, and Telus Mobility Network. Clients outside of the Calgary region did not experience any problems at all.

Now, the problem has since resolved itself, but it was ongoing for over 12 hours, which is concerning. When contacted for some sort of explanation, Network Solutions reported that they had no trouble with their service. I have opened a ticket with Cloudflare support, but have not received any response.

Being that this issue is resolved, I am looking more for an explanation as to what might have been the cause. After reviewing all of the details, it would seem that Cloudflare’s Calgary node was unable to resolve DNS from Network Solutions. But how can this be traced or verified? If NetSol can be believed and they did not experience any issues, then where could the problem have been? CF’s Calgary node’s ISP?

I can’t speak to the specific error, but, was it actually the Calgary datacentre?

I nearly always hit SEA from Calgary, every once in a while I find a hotspot that routes me to Edmonton. Other than city managed facilities (of which there are few, as Shaw runs most of the City’s public wifi) I have never seen the YYC datacentre actually answering requests.