Poll:
There appears to be DNS issues happening on multiple providers at the moment, Not nationwide but impacting Spark, Voyager, One that I've seen so far.
I can confirm that Voyager / 1st Domains is not affected although any customers might be if they have domain names with Crazy Domains. This seems to be isolated to Crazy Domains and their DNS infrastructure again. Of course any if you have your domains with Crazy Domains and they have DNS issues it will mean that websites and emails will be affected regardless of which ISP you are using.
I've seen other posters suggest not using the Registrar DNS and using Cloudflare. I'd just like to point out that if you have your domain name and DNS with 1st Domains, you get Cloudflare DNS automatically as we use Cloudflare Powered global Anycast network across 250+ cities for all domains on our DNS servers.