Error Timeout when reading response headers from daemon process?

Question

Django

Good afternoon.
I can not figure out the reasons for the Timeout when reading response headers from daemon process
web server configuration:
Server version: Apache/2.4.18 (Ubuntu)
Server built: 2017-05-05T16:32:00
WSGI
Django web application
Virtual host configuration :

<VirtualHost *:80>

    ServerName site

    WSGIDaemonProcess my_app python-path=/home/appuser/app/ processes=2 threads=25
    WSGIScriptAlias / /home/appuser/app/app_backend/wsgi.py
    WSGIProcessGroup my_app
    WSGIApplicationGroup %{GLOBAL}

    Alias /static path_to_static
    <Directory path_to_static>
        Require all granted
    </Directory>

    Alias /media path_to_media
    <Directory path_to_media>
        Require all granted
    </Directory>

    <Directory /home/appuser/app/app_backend>
        <Files wsgi.py>
            Require all granted
        </Files>
    </Directory>

</VirtualHost>