OSError: [Errno 9] Bad file descriptor #1877

I'm having this issue in raspbian image

[2018-09-10 20:40:11 +0800] [21421] [CRITICAL] WORKER TIMEOUT (pid:21699)
[2018-09-10 20:40:11 +0800] [21699] [ERROR] Socket error processing request.
Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/gunicorn/workers/async.py", line 62, in handle
six.reraise(*sys.exc_info())
File "/usr/lib/python3/dist-packages/gunicorn/six.py", line 625, in reraise
raise value
File "/usr/lib/python3/dist-packages/gunicorn/workers/async.py", line 35, in handle
listener_name = listener.getsockname()
OSError: [Errno 9] Bad file descriptor