Issue when trying to playback a video in media

Hi,

I have an issue when I try to playback an mp4 video (written from a camera stream) in the Media GUI using my NabaCasa URL or the Companion App (no matter if remotely or locally used).
When I try to start the playback the video doesn’t start. Instead most parts of the frontend get unresponsive or extremely slow until I manage to restart HA.
Using the frontend locally from my PC works like a charm all the time, even while it is unresponsive via NabuCasa or Companion App.
While it is unresponsive I see a constant load of about 7MBit/s upstream and downstream on my internet router, no matter how long I wait. (I have 250/100 fiber)
Makes no sense for playing a 16MB mp4 file…
After the restart I always find the following error message in the HA log:

Logger: homeassistant.components.http.ban
Quelle: components/http/ban.py:128
Integration: HTTP (Dokumentation, Probleme)
Erstmals aufgetreten: 12:55:39 (1 Vorkommnisse)
Zuletzt protokolliert: 12:55:39

Login attempt or request with invalid authentication from localhost (127.0.0.1). Requested URL: ‘/media/local/Klingeln/2024/03/22/Klingeln_12-49-11.mp4?authSig=#longIDhere#’. (Mozilla/5.0 (Linux; Android 12; HD1913 Build/SKQ1.211113.001; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/122.0.6261.119 Mobile Safari/537.36)

I don’t understand this issue…

Do you have an idea what’s happening and how to get rid of it?

Thanks in advance!
Tobias