The popular work messaging application Slack was offline for more than two hours on Monday, causing chaos on the first day back at work for many in 2021.
Millions of businesses have become reliant on the technology during the Covid pandemic, with remote working becoming the new normal.
But the site went down on Monday afternoon, leaving many working from home scrambling for alternatives.
On its status page, Slack said "customers may have trouble connecting or using" the messaging service.
On Twitter, the company wrote: "Our team is currently investigating and we’re sorry for any troubles this may be causing."
One business user responded: "This pretty much kills our business. I am slacks biggest fan but I just hope you folks understand what this does to us."
While another joked: "Someone in Slack is really not happy about coming back to work from long hols."