notification sound when someone joins/leaves

Hello. Try turning it off in the app. When you are in a meeting, open the Participant panel, click the three dots, and make certain Play Sound when someone joins or leaves is not checked. I added a screenshot.  If this answers your question, please click Accept as Solution.

Now, in Zoom online, you indicated you turned off Sound notification when someone joins or leaves. You want to make sure it is off. Meaning not blue. I would update the Zoom app, which should sign you out, and then sign back in. I hope this helps.