Fast Track C400 Left side only audioplayback

[Sinsanatic]

Hello good people

I have a Fast Track C400
Everything just come out in the left speaker of the headphone ? Almost its 90% Left and 10% Right. I'm going slightly mad here.
I'm running Windows 10 with the lastest driver from AVID's page

I have tested 2 headphones and 3 jack adapters by now.

In the fast Track C400 controlpanel it all looks good. Audio in both left and right. I have others have this issue, but then M-Audio says to contack AVID. Its a used interface from my cousin and she does not have the note of papir with the serial number anymore, so no help at AVID.

I know that the recording only records in the left but thats not the issue ;-)

Does anyone knows how to fix it?

Please help