I can't use libx265 or hevc with ffmpeg in ngi

Question

exec_push /usr/bin/ffmpeg -re -i rtmp://10.254.20.186:1935/$app/$name ar 44100 -vcodec libx264 -g 25 -f flv rtmp://10.254.20.186/live/$name_hi;

I can use this code in my nginx server. this is code running but dont run while write libx264 instead libx265. The interesting thing is that I can run the following commands on my linux computer without problems.

ffmpeg -i input.mp4 -c:v libx264 -crf 28 -c:a aac -b:a 128k output.mp4 ffmpeg -i input.mp4 -c:v libx265 -crf 28 -c:a aac -b:a 128k output.mp4 ffmpeg -i input.mp4 -c:v hevc -crf 28 -c:a aac -b:a 128k output264tt.mp4 ffmpeg -i input.mp4 -c:v h264 -crf 28 -c:a aac -b:a 128k output264tt.mp4