ArgumentNullException when trying to connect to Jellyfin

[NealPierceGH]

Describe the bug

I installed jellycon on kodi via the official addons repository as indicated in the README for a test run. When trying to connect to my jellyfin instance using a regular username, I get an error message on kodi UI and 2 consecutive ArgumentNullException in jellyfin logs (see below for details)

I tried to connect from CoreELEC and LibreELEC and same error every time.

To Reproduce

1. Install jellycon via recommended method in the README
2. Add manual server and provide correct URL https://jellyfin.domain.tld (valid certificate)
3. Add manual login, type in username and password as requested
4. Error occurs in kodi and exception show up in jellyfin logs

Expected behavior

Should login without issue.

1. No trouble logging in using a navigator (Chrome and Firefox)
2. No trouble with official Android app https://f-droid.org/en/packages/org.jellyfin.mobile/
3. For 1. and 2. no trouble connecting via LAN network or from internet
4. QuickConnect is disabled in my Jellyfin instance but it does not bother 1. and 2. cases

Logs

[ERR] Error processing request. URL GET /QuickConnect/Initiate.
System.ArgumentNullException: Value cannot be null. (Parameter 'authorizationInfo.DeviceId')

and

[ERR] Error processing request. URL POST /Users/AuthenticateByName.
System.ArgumentNullException: Value cannot be null. (Parameter 'request.App')

The full logs now

[ERR] Error processing request. URL GET /QuickConnect/Initiate.
System.ArgumentNullException: Value cannot be null. (Parameter 'authorizationInfo.DeviceId')
   at System.ArgumentNullException.Throw(String paramName)
   at System.ArgumentNullException.ThrowIfNull(Object argument, String paramName)
   at System.ArgumentException.ThrowNullOrEmptyException(String argument, String paramName)
   at System.ArgumentException.ThrowIfNullOrEmpty(String argument, String paramName)
   at Emby.Server.Implementations.QuickConnect.QuickConnectManager.TryConnect(AuthorizationInfo authorizationInfo)
   at Jellyfin.Api.Controllers.QuickConnectController.InitiateQuickConnect()
   at lambda_method3968(Closure, Object)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.AwaitableObjectResultExecutor.Execute(ActionContext actionContext, 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()
--- End of stack trace from previous location ---
   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()
--- End of stack trace from previous location ---
   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 Jellyfin.Api.Middleware.ServerStartupMessageMiddleware.Invoke(HttpContext httpContext, IServerApplicationHost serverApplicationHost, ILocalizationManager localizationManager)
   at Jellyfin.Api.Middleware.WebSocketHandlerMiddleware.Invoke(HttpContext httpContext, IWebSocketManager webSocketManager)
   at Jellyfin.Api.Middleware.IPBasedAccessValidationMiddleware.Invoke(HttpContext httpContext, INetworkManager networkManager)
   at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
   at Jellyfin.Api.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.Api.Middleware.RobotsRedirectionMiddleware.Invoke(HttpContext httpContext)
   at Jellyfin.Api.Middleware.LegacyEmbyRouteRewriteMiddleware.Invoke(HttpContext httpContext)
   at Microsoft.AspNetCore.ResponseCompression.ResponseCompressionMiddleware.InvokeCore(HttpContext context)
   at Jellyfin.Api.Middleware.ResponseTimeMiddleware.Invoke(HttpContext context, IServerConfigurationManager serverConfigurationManager)
   at Jellyfin.Api.Middleware.ExceptionMiddleware.Invoke(HttpContext context)

and

[ERR] Error processing request. URL POST /Users/AuthenticateByName.
System.ArgumentNullException: Value cannot be null. (Parameter 'request.App')
   at System.ArgumentNullException.Throw(String paramName)
   at System.ArgumentNullException.ThrowIfNull(Object argument, String paramName)
   at System.ArgumentException.ThrowNullOrEmptyException(String argument, String paramName)
   at System.ArgumentException.ThrowIfNullOrEmpty(String argument, String paramName)
   at Emby.Server.Implementations.Session.SessionManager.AuthenticateNewSessionInternal(AuthenticationRequest request, Boolean enforcePassword)
   at Jellyfin.Api.Controllers.UserController.AuthenticateUserByName(AuthenticateUserByName request)
   at lambda_method3975(Closure, Object)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.AwaitableObjectResultExecutor.Execute(ActionContext actionContext, 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()
--- End of stack trace from previous location ---
   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()
--- End of stack trace from previous location ---
   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 Jellyfin.Api.Middleware.ServerStartupMessageMiddleware.Invoke(HttpContext httpContext, IServerApplicationHost serverApplicationHost, ILocalizationManager localizationManager)
   at Jellyfin.Api.Middleware.WebSocketHandlerMiddleware.Invoke(HttpContext httpContext, IWebSocketManager webSocketManager)
   at Jellyfin.Api.Middleware.IPBasedAccessValidationMiddleware.Invoke(HttpContext httpContext, INetworkManager networkManager)
   at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
   at Jellyfin.Api.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.Api.Middleware.RobotsRedirectionMiddleware.Invoke(HttpContext httpContext)
   at Jellyfin.Api.Middleware.LegacyEmbyRouteRewriteMiddleware.Invoke(HttpContext httpContext)
   at Microsoft.AspNetCore.ResponseCompression.ResponseCompressionMiddleware.InvokeCore(HttpContext context)
   at Jellyfin.Api.Middleware.ResponseTimeMiddleware.Invoke(HttpContext context, IServerConfigurationManager serverConfigurationManager)
   at Jellyfin.Api.Middleware.ExceptionMiddleware.Invoke(HttpContext context)

System (please complete the following information):

• OS: LibreELEC 12.2.1 or CoreELEC NO 22.0-Piers_nightly_20260105
• Jellyfin Version: 10.11.6+ubu2404 from Jellyfin official repos
• Kodi Version: 21.3 LibreELEC or 22.0_ALPHA2 (21.90.702) CoreELEC
• Addon Version: 0.9.1