Hass.io only from one device accessible

I have installed Hass.io based on the guide from the repository hassio-build on a Raspberry Pi 3 B+ with Raspbian Stretch Lite (which has a fix IP and is accessible only via SSH) and Docker Community Edition (installed using the convenience scripts).

Now I have the problem that I can only access the Home Assistant UI via Chrome from the notebook which I have used to install Hass.io (over SSH) on the Pi. From other devices (like a Android mobile using Chrome) in the same network I can’t access the UI.

Has anyone an idea to solve this problem?

Thank you!