I was using uv4l package for streaming.suddenly it stopped working when I want run this command for example :
"sudo uv4l -nopreview —auto-video\_nr —driver raspicam —encoding mjpeg —width 640 —height 480 —framerate 20 —server-option '--port=9090' —server-option '--max-queued-connections=30' —server-option '--max-streams=25' —server-option '--max-threads=29'"

it return with this error :
 [core] No device detected

by the way uv4l is running background when it Raspberry restarts on boot and it's available on port 8080 and streams the video on <http://raspberryIp:8080/stream>
but it seem I can not start another server
Thanks in advance