Can't start Jetbrains Hub & Youtrack at the same time

I wanted to install Jetbrains Hub & Youtrack on my host. I've downloaded .zip files and extracted them to `/opt`.

I've configured them in the following way:

`bin/hub.sh configure --listen-port 3334 --base-url http://hub.example.com`

`bin/youtrack.sh configure --listen-port 3333 --base-url http://youtrack.example.com`

So I though youtrack would start at 3333 port and hub at 3334.
I've disabled SELinux (which previously caused some problems) and created Nginx rules.

ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem;

ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;

server {

    listen 443;

    server_name youtrack.example.com;

    error_log /var/log/nginx/youtrack.error.log;

    location / {

        proxy_set_header X-Forwarded-Host $http_host;

        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

        proxy_set_header X-Forwarded-Proto $scheme;

        proxy_http_version 1.1;

        proxy_pass http://localhost:3333;

    }

}

server {

    listen 443;

    server_name hub.example.com;

    error_log /var/log/nginx/hub.error.log;

    location / {

        proxy_set_header X-Forwarded-Host $http_host;

        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

        proxy_set_header X-Forwarded-Proto $scheme;

        proxy_http_version 1.1;

        proxy_pass http://localhost:3334;

    }

}

Now the problem is that I can start youtrack and access it from outside, as far as hub is not running and vice versa. But if both of them run, they restart each other. But I don't really understand, they shouldn't block each other should they? Do you have any idea about what I'm doing wrong?

I'm running this on AWS, if I allow to access ports 3334 and 3333 directly, exactly the same thing happens, so it's probably not nginx.