Unable to create NvEnc API function list: error 15

Assertion failed: Result == NV_ENC_SUCCESS [File:D:/Build/++UE4/Sync/Engine/Plugins/Media/HardwareEncoders/Source/EncoderNVENC/Private/NVENC_Common.cpp] [Line: 86] Unable to create NvEnc API function list: error 15

I have this problem when I run PixelStreaming on Windows Server 2012 R2
How can I do with this? Someone help me!