How to Train Custom Model

When I run: "./darknet detector train data/obj.data cfg/yolo-obj.cfg build/darknet/x64/darknet53.conv.74"
I get the following error: 

121 Cuda malloc failed
: No such file or directory
darknet: ./src/utils.c:277: error: Assertion `0' failed.
Aborted (core dumped)

Does anyone know how to solve this?
