Unable to play local media on mpd (mopidy)

Hi everybody. I tried to play a local m4a file on a Mopidy instance on a different server. If I try to do so with the developer → service tool everything works fine. But If I try to do so via Node Red it fails. Here is the error message:

Login attempt or request with invalid authentication from mopsam-2.fritz.box (192.168.X.X). Requested URL: 'http://192.168.X.X/media/local/10%20-%20Hass%20auf%20Bier%20-%20Die%20%C3%84rzte.m4a?authSig=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiI1NGY4OWMzYmNmN2I0NTcwYjdmN2MyNTFkMjIwMmY2OSIsInBhdGgiOiIvbWVkaWEvbG9jYWwvMTAgLSBIYXNzIGF1ZiBCaWVyIC0gRGllIFx1MDBjNHJ6dGUubTRhIiwicGFyYW1zIjp7fSwiaWF0IjoxNjc4ODAyNjA4LCJleHAiOjE2Nzg4ODkwMDh9.VLCuTDZ0nRNEP-xDc9yu5xRZ9U3w235cvYCdvnhS1Gc'. (GStreamer souphttpsrc 1.22.3 libsoup/3.4.2)

I don’t know why any authentication should be needed or why Mopidy should try to connect with Home Assistant, since it is working outside of Node Red. Can somebody help?