after Exit via Ctrl+C, Start fail again.

[he4330937]

pi@HXF-Raspberrypi:~/MyFiles/Camera/pistreaming $ python3 server.py
Initializing camera
Initializing websockets server on port 8084
Initializing HTTP server on port 8082
Initializing broadcast thread
Spawning background conversion process
Starting recording
Starting websockets thread
Starting HTTP server thread
Starting broadcast thread
10.10.10.198 - - [10/Jan/2020 10:08:44] "GET / HTTP/1.1" 301 -
10.10.10.198 - - [10/Jan/2020 10:08:44] "GET /index.html HTTP/1.1" 200 -
10.10.10.198 - - [10/Jan/2020 10:08:44] "GET /jsmpg.js HTTP/1.1" 200 -
10.10.10.198 - - [10/Jan/2020 10:08:44] code 404, message File not found
10.10.10.198 - - [10/Jan/2020 10:08:44] "GET /favicon.ico HTTP/1.1" 404 -
10.10.0.1 - - [10/Jan/2020 10:10:02] "GET / HTTP/1.1" 301 -
10.10.0.1 - - [10/Jan/2020 10:10:02] "GET /index.html HTTP/1.1" 200 -
10.10.0.1 - - [10/Jan/2020 10:10:02] "GET /jsmpg.js HTTP/1.1" 200 -
10.10.0.1 - - [10/Jan/2020 10:10:03] code 404, message File not found
10.10.0.1 - - [10/Jan/2020 10:10:03] "GET /favicon.ico HTTP/1.1" 404 -
^Z
[1]+ 已停止 python3 server.py

=====
it works fine, exit via ctrl + c .
So start it again, but fail.

pi@HXF-Raspberrypi:~/MyFiles/Camera/pistreaming $ python3 server.py
Initializing camera
mmal: mmal_vc_port_enable: failed to enable port vc.null_sink:in:0(OPQV): ENOSPC
mmal: mmal_port_enable: failed to enable connected port (vc.null_sink:in:0(OPQV))0x12456b0 (ENOSPC)
mmal: mmal_connection_enable: output port couldn't be enabled
Traceback (most recent call last):
File "server.py", line 184, in
main()
File "server.py", line 134, in main
with picamera.PiCamera() as camera:
File "/usr/lib/python3/dist-packages/picamera/camera.py", line 433, in init
self._init_preview()
File "/usr/lib/python3/dist-packages/picamera/camera.py", line 513, in _init_preview
self, self._camera.outputs[self.CAMERA_PREVIEW_PORT])
File "/usr/lib/python3/dist-packages/picamera/renderers.py", line 558, in init
self.renderer.inputs[0].connect(source).enable()
File "/usr/lib/python3/dist-packages/picamera/mmalobj.py", line 2212, in enable
prefix="Failed to enable connection")
File "/usr/lib/python3/dist-packages/picamera/exc.py", line 184, in mmal_check
raise PiCameraMMALError(status, prefix)
picamera.exc.PiCameraMMALError: Failed to enable connection: Out of resources

==================

How to exit? I hope works fine when start it again.