SOLVED: Jellyfin and Mopidy no Connection

[Computerboss]

Good evening everyone,

I have been trying to establish a connection between my Mopidy instance on my Raspberry Pi and the Jellyfin server for several hours, unfortunately without success.

I use Jellyfin in Docker on my Synology NAS.
I establish the connection from the PC via a domain, which is resolved via the reverse proxy of the NAS and points to the Docker application.

Alternatively, I have already tested that I release the Jellyfin port 8096 on the NAS directly and you can access the Jellyfin instance with HTTP.

I have configured Mopidy exactly according to the Jellyfin instructions:

https://jellyfin.org/docs/general/clients/mopidy/

From the section:
Raspberry Pi (Remote Controlled Speakers)

I have tried both the FQDN and the IP address of the Jellyfin server. Even with port :8096 it didn't work...

Here are three example configurations:

[jellyfin]
enabled = true
hostname = sub.domain.synology.me
username = mopidy
password = Test4543
libraries = Musik


[jellyfin]
hostname = 192.168.1.122
username = mopidy
password = Test4543



[jellyfin]
hostname = sub.domain.synology.me
user_id = mopidy
token = 34234234234234324234234234


nothing worked
Mopidy works though, I installed the TuneIn application and it worked straight away!

I would be very happy if someone has an idea?

Are the instructions at Jellyfin still up to date?

Best regards