Zoom has a global outage that is preventing users from joining meetings or seeing video and audio once they have joined. There is currently no indication as to when the issue will be resolved. Update: Zoom states that the issue has been fixed and that users should log out of their session and try again. Until this is resolved, Zoom meetings will not work until the issue is resolved. The Zoom status page states that this is only affecting a small subset of users and that Zoom is “continuing to investigate this issue”””
Source: https://www.bleepingcomputer.com/news/software/zoom-global-outage-preventing-meetings-video-and-audio/

