Unable to execute script file using cron tab

I have a question about Crontab.
I want to run the jetson-inference code(https://github.com/dusty-nv/jetson-inference/blob/master/docs/pytorch-collect.md) when I start jetson. So I used crontab and I get an error.
When I looked at the log, I saw the following error.

    display = jetson.utils.glDisplay()Exception: jetson.utils -- failed to create glDisplay device

I don’t know what caused this error.

By the way, I will run into the same error if I did with the other jetson-inference examples. For example this one (https://www.youtube.com/watch?v=bcM5AQSAzUY&t=1181s)

Furthermore, nvgstcapture was able to automatically start the camera, so I think that the reason why crontab does not work is in jetson.utils.glDisplay.

If you know the cause, can you tell me.

Thanks for the great demo code.
Thank you