Issue Setting up YouTrack on custom subdomain on Ubuntu 14.04 with Plesk Onyx 17.5

[Fabs87]

I want to set up YouTrack standalone on my webserver using the zip-Version.

I've uploaded and extracted all files on my server and I've created a subdomain (board.domain.de). Then I've configured YouTrack wo use another base url and to listen to another port:

./youtrack.sh configure --listen-port 1111 --base-url https://board.domain.de:2222

This is the output:

    * Configuring JetBrains YouTrack 2018.1
    * Setting property 'listen-port' to '1111' from arguments
    * Setting property 'base-url' to 'https://board.domain.de:2222' from arguments
    * JetBrains YouTrack 2018.1 runtime environment is successfully configured
    * Loading logging configuration from /var/www/vhosts/domain.de/board.domain.de/youtrack-2018/lib/ext/log4j.xml
    * Redirecting JetBrains YouTrack 2018.1 logging to /var/www/vhosts/domain.de/board.domain.de/youtrack-2018/logs/internal/services/bundleProcess
    * Configuring Service-Container[bundleProcess]
    * Configuring Bundle Backend Service
    * Configuring Configuration Wizard

Then I've started YouTrack via ``./youtrack.sh start`` which worked fine without any errors. Output:

    Starting YouTrack...
    * Configuring JetBrains YouTrack 2018.1
    * JetBrains YouTrack 2018.1 runtime environment is successfully configured
    * Loading logging configuration from /var/www/vhosts/domain.de/board.domain.de/youtrack-2018/lib/ext/log4j.xml
    * Redirecting JetBrains YouTrack 2018.1 logging to /var/www/vhosts/domain.de/board.domain.de/youtrack-2018/logs/internal/services/bundleProcess
    * Configuring Service-Container[bundleProcess]
    * Configuring Bundle Backend Service
    * Configuring Configuration Wizard
    * Starting Service-Container[bundleProcess]
    * Starting Bundle Backend Service
    * Starting Configuration Wizard
    * JetBrains YouTrack 2018.1 Configuration Wizard will be available on [https://board.domain.de:2222/?wizard_token=7bDc4UyhjyLFPmlJhkzm] after start
    YouTrack is running

Clicking on the shown url, my browser opens but shows me an error. Website not reachable (``ERR_CONNECTION_REFUSED``). I thinks this has something to do with my apache/nginx configuration. So I've followed these instructions to configure reverse proxy.

So, in Plesk under my subdomain-settings I've edited the common apache settings:

Nginx is configured to work as proxy for apache.

But I still get the error from above. What am I doing wrong?