I just installed Zammad and I am configuring it. But when I access to the login page there is the messages on top: Log in to 10.xxx.xxx.xxx
even if I log from a public IP.
To change it I need to apply changes/recompile or there is some configuration hint?
It sounds like you didn’t set a hostname for your instance. In Admin go to System under the settings heading. Under Fully Qualified Domain Name enter the URL for your instance and submit. The IP on that page should change to the hostname of your page.