try adding headers

apps/media/ingress.yaml

@@ -29,6 +29,7 @@ spec:
     - match: Host(`media-backend.kluster.moll.re`)
       middlewares:
         - name: jellyfin-websocket
+        - name: jellyfin-server-headers
       kind: Rule
       services:
         - name: jellyfin-server
@@ -46,3 +47,18 @@ spec:
     customRequestHeaders:
       X-Forwarded-Proto: "https"
       Upgrade: "websocket"
+
+---
+apiVersion: traefik.containo.us/v1alpha1
+kind: Middleware
+metadata:
+  name: jellyfin-server-headers
+  namespace: media
+spec:
+  headers:
+    customResponseHeaders:
+        accessControlAllowCredentials: true
+        accessControlAllowHeaders: [ "Authorization","Content-Type" ] # "Accept","Origin"
+        accessControlAllowMethods: [ "GET","HEAD","OPTIONS" ] # "POST","PUT"
+        accessControlAllowOriginList: "*"
+        accessControlMaxAge: 100