WEBEX audio not working in my MAC laptop: OS X El Capital Version 10.11.3, Mozilla Firefox 44.0.2. & Wifi eduroam conection

Dear Sir/Madam,

From the beginning of my attempt to use webex on 15th January 2016, I have been facing BIG TROUBLES with the AUDIO:

- initially to be heard.

- today also, to hear others.

The connection and the sessions goes well but the AUDIO is not working in my laptop.

Here the specifications:

Laptop:

OS X El Capitan

Version 10.11.3

MacBook Pro (Retina, 15-inch, Mid 2014)

Processo 2.5 GHz Intel Core i7

Memory 16 GB 1600 MHz DDR3

Graphics NVIDIA GeForce GT 750M 2048 MB

Seriel Number C02NT2Q7G3QD

Browser:

Mozilla Firefox 44.0.2

Wifi connection at the University of Oxford:

Eduroam

ANY SORTS OF WAY TO FIX IT?

Thanks in advance

Kind regards