SOLVED: Jellyfin hangs up when playing video

[intael]

Some context:
I'm using Jellyfin.Server 10.8.13.0 on Debian GNU/Linux 12 (bookworm) x86_64. Jellyfin was installed using the automatic method here.
The client is an LG TV, the model is: [LG] webOS TV UH661V

I'm getting the following exception from the logs when trying to play a video. The video does not play and is not sent to the client. This happens with any video I attempt to play.

Code:

[2023-12-02 21:33:50.720 +02:00] [ERR] [46] Jellyfin.Server.Middleware.ExceptionMiddleware: Error processing request. URL "POST" "/Sessions/edbd1fd5e96c87db15f6c027e0d7d404/Playing".
System.Net.Http.HttpRequestException: Response status code does not indicate success: 500 (Internal Server Error).
  at System.Net.Http.HttpResponseMessage.EnsureSuccessStatusCode()
  at Emby.Dlna.PlayTo.SsdpHttpClient.SendCommandAsync(String baseUrl, DeviceService service, String command, String postData, String header, CancellationToken cancellationToken)
  at Emby.Dlna.PlayTo.Device.SetAvTransport(String url, String header, String metaData, CancellationToken cancellationToken)
  at Emby.Dlna.PlayTo.PlayToController.SetPlaylistIndex(Int32 index, CancellationToken cancellationToken)
  at Emby.Dlna.PlayTo.PlayToController.PlayItems(IEnumerable`1 items, CancellationToken cancellationToken)
  at Emby.Server.Implementations.Session.SessionManager.SendMessageToSession[T](SessionInfo session, SessionMessageType name, T data, CancellationToken cancellationToken)
  at Emby.Server.Implementations.Session.SessionManager.SendPlayCommand(String controllingSessionId, String sessionId, PlayRequest command, CancellationToken cancellationToken)
  at Jellyfin.Api.Controllers.SessionController.Play(String sessionId, PlayCommand playCommand, Guid[] itemIds, Nullable`1 startPositionTicks, String mediaSourceId, Nullable`1 audioStreamIndex, Nullable`1 subtitleStreamIndex, Nullable`1 startIndex)
  at lambda_method1346(Closure , Object )
  at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.TaskOfActionResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments)
  at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeActionMethodAsync>g__Awaited|12_0(ControllerActionInvoker invoker, ValueTask`1 actionResultValueTask)
  at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeNextActionFilterAsync>g__Awaited|10_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
  at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow(ActionExecutedContextSealed context)
  at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
  at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeInnerFilterAsync>g__Awaited|13_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
  at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeNextResourceFilter>g__Awaited|25_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
  at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResourceExecutedContextSealed context)
  at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
  at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeFilterPipelineAsync>g__Awaited|20_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
  at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)
  at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)
  at Microsoft.AspNetCore.Routing.EndpointMiddleware.<Invoke>g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)
  at Jellyfin.Server.Middleware.ServerStartupMessageMiddleware.Invoke(HttpContext httpContext, IServerApplicationHost serverApplicationHost, ILocalizationManager localizationManager)
  at Jellyfin.Server.Middleware.WebSocketHandlerMiddleware.Invoke(HttpContext httpContext, IWebSocketManager webSocketManager)
  at Jellyfin.Server.Middleware.IpBasedAccessValidationMiddleware.Invoke(HttpContext httpContext, INetworkManager networkManager)
  at Jellyfin.Server.Middleware.LanFilteringMiddleware.Invoke(HttpContext httpContext, INetworkManager networkManager, IServerConfigurationManager serverConfigurationManager)
  at Microsoft.AspNetCore.Authorization.Policy.AuthorizationMiddlewareResultHandler.HandleAsync(RequestDelegate next, HttpContext context, AuthorizationPolicy policy, PolicyAuthorizationResult authorizeResult)
  at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
  at Jellyfin.Server.Middleware.QueryStringDecodingMiddleware.Invoke(HttpContext httpContext)
  at Swashbuckle.AspNetCore.ReDoc.ReDocMiddleware.Invoke(HttpContext httpContext)
  at Swashbuckle.AspNetCore.SwaggerUI.SwaggerUIMiddleware.Invoke(HttpContext httpContext)
  at Swashbuckle.AspNetCore.Swagger.SwaggerMiddleware.Invoke(HttpContext httpContext, ISwaggerProvider swaggerProvider)
  at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
  at Jellyfin.Server.Middleware.RobotsRedirectionMiddleware.Invoke(HttpContext httpContext)
  at Jellyfin.Server.Middleware.LegacyEmbyRouteRewriteMiddleware.Invoke(HttpContext httpContext)
  at Microsoft.AspNetCore.ResponseCompression.ResponseCompressionMiddleware.InvokeCore(HttpContext context)
  at Jellyfin.Server.Middleware.ResponseTimeMiddleware.Invoke(HttpContext context, IServerConfigurationManager serverConfigurationManager)
  at Jellyfin.Server.Middleware.ExceptionMiddleware.Invoke(HttpContext context)

[intael]

This got solved by unplugging the TV and switching it on again

[TheDreadPirate]