Slack is back after an outage that started around 11.30am NZT.
The US-based company had no immediate word on the cause of the foul-up.
In a blow to many working from home, the workplace messaging service suffered a global outage from late morning.
The failure left many businesses returning to email and phone calls to communicate.
Slack acknowledged the issue on Twitter, writing: "Users have reported general performance issues such as message sending failures and timeouts."
Users began reporting that some service was returning at 12.30pm.
Some users were very dramatic about the effect the outage was having.
In some time zones, the outage was perfectly timed:
Not sure what this tweet says, but it is brilliant: