No audio using headset

I'm using a headset and I have no audio

A frequent cause is that the headset is plugged into the wrong port on the back of the phone. There are two ports, one for HANDSET and one for HEADSET. These can easily be mistaken so please make sure that the headset is in the headset port.

If you are using a softphone like 3CX for example, the headset will most likely be plugged in using the USB port on your laptop/PC/Mac. On 3CX, you can right click on the screen and hit “Debug” – anything in RED is an error, or you could try plugging it into another USB port on the machine.