As reported by engadget,
So much for a smooth return to work after the holidays. Your first day back at the office (or your desk at home) might have been disrupted when Slack experienced serious issues on Monday morning. At first, the incident was somewhat limited as messages were not loading for many users. Others were having connection problems. By around 11:20am ET, Slack was experiencing a full-blown outage, according to its status page.
Slack said “all hands are on deck on our end” as it tries to get to the bottom of the outage, which is far from the company’s first. Slack hasn’t given an estimate of how long it’ll take to resolve the problem, though it will continue to share updates on the status page. In the meantime, perhaps it’s time for another sandwich packed with leftovers.