Having problems with VOIP Integration

I have tried to install the VOIP integration.
Unfortunately, I cannot detect an open port 5060 on UDP as well as TCP.

I tried to debug the whole thing via Home Assistant OS, but I could not get into the root user via the “CONFIG” USB stick, because the file converted as ANSI is always reloaded as UTF8.

In the log home-assistant.log is only the following:
2023-07-09 18:02:39.707 DEBUG (MainThread) [homeassistant.components.voip] Shutting down VoIP server
2023-07-09 18:02:39.709 DEBUG (MainThread) [homeassistant.components.voip] VoIP server shut down successfully
2023-07-09 18:02:39.712 DEBUG (MainThread) [homeassistant.components.voip] Listening for VoIP calls on port 5060

#Push Thread

Any Ideas?

Issue: VOIP Server not comming up · Issue #96210 · home-assistant/core · GitHub