Home Assistant not Available without Internet

Hello all,

I have the following problem.

Home Assistant does not want to start without internet.

Means when Home Assistant is (re)started, and there is no internet connection HA is no longer accessible.
Neither via the Nabu Casa URL (as far as clear without Internet) but also via the local IP address (192.168.X.X:8123) or DNS homeassistant.local:8123.

If I reboot HA and there is an internet connection, everything boots up normally as if nothing ever happened.

The following setup:

  • Raspberry Pi 4, 64-bit with 16GB SD card.
  • Nabu Casa Remote URL active
  • Standard router without firewall configuration (FritzBox)