The message you obtain when installing Phabricator says:
Hostname that will be used to create internal URLs. If this value is incorrect,
you may be unable to access your Phabricator installation from other computers.
I recommend you to use the default value the installer auto-detects. Later on, if your server has the domain
projectirene.de. You can configure Phabricator running:
/opt/bitnami/apps/phabricator/bnconfig --machine_hostname YOUR-DOMAIN
Please take in mind that you have to use as "Machine Hostname" the Domain you are using to access your Phabricator. If you are going to access it via localhost (127.0.0.1), the Machine Hostname should be 127.0.0.1.
I hope this information is useful for you. If you have any other question, please do not hesitate to let us know.