Jabber will need permission to use your microphone on your Macbook. Please follow these steps to give the permission.
Completely close Jabber
Click on the Apple in the top left and corner and click on System Preferences
With the new window you are looking for Security & Privacy click on it
From here on the left hand side you should see Microphone it will be close to the bottom, click on it
To the right you will see the apps that can use your Mic, check mark Cisco Jabber
This gives Jabber the permission it needs to use your mic.
If you have any issues please submit a ticket to help.gcisd.net