Now someone else says it was a #regex issue that brought down #CloudFlare #DNS ... which also happened last year (2019-07-02, according to #Wikipedia). I have not gone looking for an authoritative source, so consider this an unconfirmed rumor.
>We had an issue that impacted some portions of the @Cloudflare
> network. It appears that a router in Atlanta had an error that caused bad routes across our backbone. That resulted in misrouted traffic to PoPs that connect to our backbone. 1/2
>We isolated the Atlanta router and shut down our backbone, routing traffic across transit providers instead. There was some congestion that caused slow performance on some links as the logging caught up. Everything is restored now and we're looking into the root cause. 2/2