SOLVED: Apps cant connect to Jellyfin from externally

[emperor_bln]

Thanks, but i deeply dislike docker ^^
I now went another route
I registered (completely free) at https://desec.io/
pointed my domain nameservers at ns1.desec.io & ns2.desec.org
created a simple dns.sh script that does a "curl --user jelly.mydomain.de:mysecrettoken https://update.dedyn.io/" for every subdomain
went into "crontab -e" and added it as "0 * * * * /usr/bin/dns.sh"
now I see nice clean A-Records and everything works

hope this can help other people in the future with the same problem