Slack went down worldwide for roughly an hour Tuesday evening, leaving companies scrambling to communicate right at the end of the U.S. workday.

The chat app went down around 4:53 p.m. PT on Tuesday, according to Slack’s Status page. Service began to come back about an hour later, around 5:50 p.m.

“Users have reported general performance issues such as message sending failures and timeouts,” Slack wrote. “We’re working to get things back to normal as quickly as possible and will provide an update shortly.”

By 5:02 p.m. PT, the company posted another update: “Users are unable to connect to Slack. We are investigating and will provide an update shortly”.

At least 5,000 users reported issues with Slack on Downdetector, including problems connecting and sending messages. Slack for Windows and Mac, along with the Slack mobile and web apps, all seemed to be affected by the outage.

Some users couldn’t get Slack to load at all, seeing only an error message: 503 Service Unavailable.

On Twitter, Slack users said they were unable to write messages, with some Slack channels appearing completely blank.

By about 5:39 p.m. PT, some users said that service had been restored, though others said that the app still wasn’t working.

My connection got fixed! Slack always the best!

— Doug E. Fresh (@DFresh505) May 13, 2020

At the very least — for better or worse — email was still working, meaning you could still communicate with you co-workers, just much more slowly.

2020 also decided we're all reverting back to email thread conversations. #SlackDown pic.twitter.com/fmoLjWHsb5

— Danna Fakhoury (@dannadano) May 13, 2020

We’ve reached out to Slack for more information on the outage and will update this story as soon as we hear back.

This is a breaking news story and will be updated.