Unreal and OSVR display problem

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Hello,
I have this problem with unreal when i want to use from osvr plugin :

FOSVRCustomPresentLog:Warning: osvrRenderManagerOpenDisplayD3D11 call failed, or the result status was OSVR_OPEN_STATUS_FAILURE. Potential causes could be that the display is already open in direct mode with another app, or the display does not support direct mode

I'm using from HTC Vive headset and I installed osvr-vive & osvr-steamvr & osvr server
And my graphic card is gigabyte gtx 1070 and driver version : 384.76

please help , thanks.