Suddenly my professional SPDIF coax out channel stopped working.

I have been using my setup for several years. Not changing any setup.

Now suddenly I don't get any sound from my SPDIF coax digital out channel. I can see audio being played in the TotalMix mixer.

I have the latests 3.35 2.77 driver installed. I am on OSX 10.13.6

HOWEVER, if I deselect the SPDIF Out Professional tick box. And the select the same tick box again. I do get audio for a few seconds before it starts to stutter and slowly fade out.

I just can't figure out what I might have done to cause this.

Any advice or idea on how to trouble shoot would be kindly appreciated

/K