Slack is down, time to slack

Slack, the popular biz-oriented chat service, is down for many users this morning. 
The company confirmed the issues which people were reporting (me included) early Tuesday. 
SEE ALSO: Slack returns for all after being down for a blissful moment in time
"We're investigating as we speak," the tweet said, but no reasons behind the outage were given. If we learn the reasons, we'll share them here. 
UPDATE: Sept. 11, 2018, 11:19 a.m. CEST Slack says the service is back up now. So