So although it's the same domain, slack.com, the records still resolve which seems to rule out a DNS related issue. DNS is served by AWS Route53 in all cases and only by Route53 (which might or might not be a great idea considering what happened to Dyn late last year).
Slack.com and the API are hosted by EC2, status.slack.com points to Rackspace.
Slack.com and the API are hosted by EC2, status.slack.com points to Rackspace.
I wonder what happened to take both down.