New to JamKazam and no audio even on setup

[charlie.i]

Just to round off this thread, it was mostly my stupidity, though it's not immediately obvious what to do when you first set up. Thanks to the various contributions I realised that playback HAS to be though the audio interface - in my case the Focusrite Scarlet 616.  That means monitoring through headphones.  It also means using the Focusrite app - it didn't work without it.
Thanks for the advice.  I now have lovely clear audio in and out.
Charlie