nginx not showing anything

I seem to have a problem with my nginx.

I just deployed a Flask app on an AWS EC2 instance and linked it to my subdomain (let’s call it subdomain.domain.com). Everything was working correctly, my app running on port 5001, I installed nginx to redirect traffic coming through port 80. And I did manage to do it. The problem came when I installed the let’s encrypt certificates using certbot.

I did not receive any error message, yet navigating to subdomain.domain.com was no longer doing anything apart from giving me a ERR_CONNECTION_TIMED_OUT.

I tried several things and check every configuration, recreated the certificates, restarted nginx service, but nothing worked. So I decided to start from scratch, uninstall nginx and reinstall it, but the problem persists.

For further information:

• My EC2 instance accepts requests on port 80 and 5001.

• nginx error log dos not show any error apart from an "aborting" message that just appeared right now
  

• nginx service status shows it’s active
  

• Right now I don’t have my site symlinked so I should not see it, but I should see Nginx Welcome page which is not the case

    server {
        listen 80;
        server_name subdomain.domain.com;
  
        location / {
            include proxy_params;
            proxy_pass http://<aws-private-ip>:5001;
        }
    }
  

• UFW firewall shows as inactive, so I understand that is not the problem

• I tried to kill all 80/tcp processes and restart nginx but it did not do a thing

• I tried to use nginx -s reload but nothing changed

• This my netstat plant on port 80 result
  

• The app is running and the server is indeed up, running and accessible since I can see the app opening subdomain.domain.com:5001 on my browser

Could someone point me towards other things I can try?

Thanks in advance