Slack’s Pandemic Growth Takes Hit From Disappointing Billings

Slack Technologies Inc. enjoyed strong customer growth even as some users cut back on use of the workplace-collaboration tool, showing how pandemic-driven changes have been both a boon and burden for business-software firms.

Investors have bet heavily on businesses poised to benefit from the changes the pandemic has caused in the lives of millions of Americans as they work from home. Zoom Video Communications Inc. last week lifted its full-year outlook for the second time during the pandemic and business-software provider…