External users can't access my App running on a EC2 instance. The EC2 Instance can access the internet.

Hi Riku. Thank you for your thoughts. To answer your question about Gunicorn, yes I have set up the configuration in Nginx and Gunicorn to work in tandem. However, let me look at the conf file you sent to see if it is equivalent to what I have done. About the "chdir" setting in "settings.py", do youi mean setup.py to create the wheel file? I am not aware of a "settings/py" script. Please elaborate.

The official documentation is below. The default file name is "gunicorn.conf.py". https://docs.gunicorn.org/en/stable/settings.html

Hi Riku. Thanks for the link. I see what you are talking about. My Gunicorn setup is as follows:

[Unit] Description=Gunicorn instance to serve merysol_advisor After=network.target

[Service] User=ubuntu Group=www-data WorkingDirectory=/home/ubuntu/merysol_advisor Environment="PATH=/home/ubuntu/m/erysol_advisor/venv/bin" ExecStart=/home/ubuntu/merysol_advisor/venv/bin/gunicorn --workers 3 --bind unix:merysol_advisor.sock -m 007 wsgi:app

[Install] WantedBy=multi-user.target

And, my nginx configuration is:

server { listen 80; listen 443; server_name merysol.com www.merysol.com;

location / {
    include proxy_params;
    proxy_pass http://unix:/home/ubuntu/merysol_advisor/merysol_advisor.sock;
}

}

When I run the command nginx -t , I get good feedback so I think the configuration is correct.
I will go through some of the testing options in the unicorn.conf link you sent me to see if I can find the problem -Umberto

While sending you Riku my last comment, I realized I had a typo in the Gunicorn configuration. I had : Environment="PATH=/home/ubuntu/m/erysol_advisor/venv/bin"

I fixed it and restarted the Gunicorn service and nginx but there was no change in the behavior. I also notice that trying to acces nginx using https fails with ERR_SSL_PROTOCOL_ERROR in Chrome. This usually means that it is being blocked by the firewall. But I certainly have rules to allow 443 both in the security group and in the ufw.

Thank you for sharing the detailed configuration. ERR_SSL_PROTOCOL_ERROR" can occur if the SSL certificate is incorrectly configured. Looking at the Nginx configuration, it appears that the SSL certificate is not configured, where is the SSL certificate configured?

Hi again Riku, Well I have added a new SSL Certificate to the app and configured the AWS Load Balancer to send HTTP and HTTPS traffic ot he App. Howeverm the openssl command still doesn't show the certificate. Is there some additional magic to associate the certificate to the App in AWS? This things is certianly frustrating. Isn't it? -Umberto

If you have ALB, you may not need to set up certificates in EC2. I think we can set up an SSL certificate in ACM for the ALB and set up an HTTPS listener. https://docs.aws.amazon.com/elasticloadbalancing/latest/application/create-https-listener.html
Also, am I correct in understanding that EC2 is listening on HTTPS? In that case, I think you need to set the listener protocol to HTTPS in the target group settings, is it set?