Motu Traveler Pb, no sounds comes outside Options

[rogaroga]

Hello

Since a few day, my Motu Traveler doesn't work at all with ableton live.
if the software output is set on the traveler, I have no sound coming out of the software, but only squealing (but it works well if i choose the mac output).

here is what i tried to solve the problem:
- I re-install my full system (macosX, drivers and software)
- I tried on an other Mac, but the problem is the same

Other things which could help to undertand the problem:
- the traveler still works well as and a standalone mixer: i use different inputs, and the sound comes out normaly.
- Itunes works well with the traveler, until i launch ableton Live. Then i can't here squealings from Itunes as well.

If someone could help ?

thank you