DeckLink 4k Extreme 12g - Problem Audio Channels

We have a problem with our PCI card, impossible to have more than 2 audio channels..

Scenario:

- Movie *.mxf with 8 audio channels.
- Windows 10 prof.
- DELL Tower 3630.
- Blackmagic Desktop Video 10.11.4
- Shotcut for video player
- Analyser connected to SDI Out.

PLEASE WE NEED HELP!!

THKS.