SSL Connex is muted (red Solid State Logic logo).
Ensure the Solid State Logic logo is not red. Tap the Solid State Logic logo to toggle the mute state.
Video conferencing application is muted.
Ensure the application is not muted (usually denoted by a microphone symbol with a line/cross through it).
Incorrect input device selected in the application.
Navigate to the audio devices settings in the application and ensure the audio input is set to “Microphone - SSL Connex”