AUSTIN (KXAN) — Internet messaging tool Slack went down for many users around 9:30 a.m. Eastern Time on Monday, knocking out a key communication tool for businesses.

The website downdetector.com shows the bulk of outage reports starting just before 10 a.m. with a peak of nearly 17,000 outage reports by 9:10 a.m. Users could not connect to the service, or if they were already logged in, they couldn’t send messages. Intermittent issues continued for over two hours, with the bulk of the outage reports tailing off before 1 p.m.

The company acknowledged the outage on its status account, @SlackStatus, at 9:14 a.m. The account did not give an exact timetable for the service to be returned.

Problems with the service in the U.S. have been reported in major metropolitan areas New York, Chicago, Boston, Washington, D.C., Detroit, Los Angeles, San Francisco, Phoenix, Dallas, Houston and in Austin.

The website’s status page says the company is still looking into the issue.

Slack was purchased by Salesforce in December.