"cant hear person calling in"
"Person calling can't hear me"

Check first - Is headset default in and out device?

if:

No - make sure headset plugged in - Mic not muted and 3CX Sees it as default in/out audio device.
Yes - Check WaveMaxx audio - Stop it from running in TM, Disable as a startup item, uninstall if possible


If you disable WavesMaxx - test the headset, if you can hear other sounds through it (youtube, system sounds etc)

but 3CX is still silent, go to settings > Scroll to Audio Options > Make sure "Microphone" "Speaker" and "Ringer" are all set to Jabra headset.


Make sure "Headset" button is checked.

This should resolve any issue with 3CX Sounds.