Conversations involving multiple participants, allowing collaboration and information sharing in Teams
I'm having the same problem on both Edge and Chrome on Linux and on Teams for Linux unofficial app. If I had to guess the fact that Teams blocks any sounds if you have an active window is the culprit. It's the only thing that makes sense to cause 3 different programs to all fail to make any sound when I'm in 4th program, Discord, which has zero problems sending me notices of messages. Same with Google Chat working just as expected. They're all configured to send me sounds from direct messages regardless of what window is active. Teams is the only one that doesn't let me override that silly "feature" and so I must conclude it's to blame.