Cast Button find no device

[brauni]

I have set up jellyfin 10.10.6 on a Synology in a Docker container since a view days. Today I noticed that the cast icon function no longer works.
Previously, after clicking on the icon, my Chromecast sticks and some DLNA devices such as the TV were displayed for selection. This no longer works.
When I click on the cast icon, no selection appears.

I was able to reproduce this in both the Chrome/Firefox browser and the Android app jellyfin. Other apps like Netflix don't have this problem

The following entry can be found in the logbook, after the click on the cast-icon:

Code:

[2025-03-14 23:25:16.926 +00:00] [ERR] [12] Jellyfin.Api.Middleware.ExceptionMiddleware: Error processing request. URL "GET" "/Sessions".
System.InvalidCastException: Unable to cast object of type '<>z__ReadOnlyArray`1[MediaBrowser.Model.Session.GeneralCommandType]' to type 'MediaBrowser.Model.Session.GeneralCommandType[]'.
  at System.Text.Json.JsonSerializer.UnboxOnWrite[T](Object value)
  at System.Text.Json.Serialization.JsonConverter`1.WriteAsObject(Utf8JsonWriter writer, Object value, JsonSerializerOptions options)
  at System.Text.Json.Serialization.JsonConverter`1.TryWrite(Utf8JsonWriter

What could be the cause? I dont know what is changed, so it doesnt work anymore,
I have completely reinstalled jellyfin but without success. Also i have already searched the Internet for information on this, but have not found anything.

Many Thanks for any idea,
Andreas