After using Zoom some of the audio and mic settings automatically get changed on Jabber resulting on people not being able to hear the other person or being able to talk through the mic, below there are the steps to change the settings on Jabber to the default ones.
1. First make sure to close Zoom then re open Jabber, go to preferences under the Jabber menu below
2. Select the Audio Video tab, make sure that under Audio Call Output, MacBook Air Speakers is selected.
3. Check that Microphone is selected on MacBook Air Microphone.