UWSGI CRITICAL: could not connect() to workers Operation now in progress

uwsgi --nagios --socket=0.0.0.0:1717

description "uwsgi instance"
start on runlevel [2345]
stop on runlevel [06]

exec uwsgi --master --die-on-term --ini /etc/uwsgi/apps-enabled/my-app.com

[uwsgi]
uid = www-data
gid = www-data
plugins = python

module= wsgi_app
home = /home/django/domains/my-app.com/my-app.com/
pythonpath = /home/django/domains/my-app.com/my-app/uwsgi/
touch-reload = /home/django/domains/my-app.com/my-app/uwsgi/restart.trig
socket = /tmp/my-app.com.socket
logto = /var/log/uwsgi/my-app.com.log
enable-threads = true
single-interpreter = true

listen=4000
threads = 5
workers = 10
master = true
max-requests=1000
buffer-size = 32768
post-buffering = 8192