Permission "Grant access" in WebUI takes very long in RDM gets timeout or not connection

Hello everyone,

First of all, I would like to thank you for your excellent support. I have always received quick and helpful answers.
I really like the new web interface in version 2025.3.x. I think the similarity to RemoteDesktopManager is very well done.

And that brings me to my problem.
Since we started using 2025.3.x, adjusting permissions in Security -> Permissions -> Grant Access in the WebUI has been very to extremely slow.
In 2025.3.4.0, it takes up to a minute for the “window” for adjusting permissions to open in the WebUI.
In 2025.3.5.0, I have to admit, I have never waited that long for the “window” to open or for a timeout to occur. Here in the WebUI as well.

In RemoteDesktopManager, after a short time, I receive a message saying that no connection to the data source could be established and asking if I want to switch to offline mode. If I confirm with “NO” here:

Error message dialog
Value cannot be null (Parameter 'source')

ArgumentNullException - Value cannot be null. (Parameter 'source')

at System.Linq.ThrowHelper.ThrowArgumentNullException(ExceptionArgument argument)
at System.Linq.Enumerable.Any[TSource](IEnumerable1 source, Func2 predicate)
at Devolutions.RemoteDesktopManager.AvaloniaUI.ViewModels.BatchGrantPermissionViewModel.FillLists(Boolean isHubReportAnIssue, Boolean isHubSendSecureMessage, Boolean isHubGatewayPermissions)
at Devolutions.RemoteDesktopManager.AvaloniaUI.ViewModels.BatchGrantPermissionViewModel.InitializePermissions()
at Devolutions.RemoteDesktopManager.AvaloniaUI.ViewModels.BatchGrantPermissionViewModel..ctor(ConnectionEngine engine, Boolean hasViewPassword, Boolean hasViewSensitive, Boolean hasCustomInherited, Boolean isPam)
at Devolutions.RemoteDesktopManager.AvaloniaUI.ViewModels.PermissionsViewModel.GrantAccess()
at Avalonia.Data.Core.ExpressionNodes.MethodCommandNode.Command.Execute(Object parameter)
at Avalonia.Controls.Button.OnClick()
at Avalonia.Controls.Button.OnPointerReleased(PointerReleasedEventArgs e)
at Avalonia.Reactive.LightweightObservableBase1.PublishNext(T value) at Avalonia.Interactivity.EventRoute.RaiseEventImpl(RoutedEventArgs e) at Avalonia.Interactivity.EventRoute.RaiseEvent(Interactive source, RoutedEventArgs e) at Avalonia.Interactivity.Interactive.RaiseEvent(RoutedEventArgs e) at Avalonia.Input.MouseDevice.MouseUp(IMouseDevice device, UInt64 timestamp, IInputRoot root, Point p, PointerPointProperties props, KeyModifiers inputModifiers, IInputElement hitTest) at Avalonia.Input.MouseDevice.ProcessRawEvent(RawPointerEventArgs e) at Avalonia.Controls.TopLevel.<>c.<HandleInput>b__150_0(Object state) at Avalonia.Threading.Dispatcher.Send(SendOrPostCallback action, Object arg, Nullable1 priority)
------------------------ extended stack ------------------------
at Devolutions.RemoteDesktopManager.Forms.FrmErrorMessage.ShowErrorMessage(ConnectionEngine engine, Exception exception, String message, String title)
at Devolutions.RemoteDesktopManager.Managers.LogManager.HandleException(Exception exception)
at Devolutions.RemoteDesktopManager.Managers.LogManager.OnThreadException(Object sender, DispatcherUnhandledExceptionEventArgs e)
at Avalonia.Threading.Dispatcher.CatchException(Exception e)
at Avalonia.Threading.Dispatcher.Send(SendOrPostCallback action, Object arg, Nullable`1 priority)
at Avalonia.Controls.TopLevel.HandleInput(RawInputEventArgs e)
at Avalonia.Win32.WindowImpl.AppWndProc(IntPtr hWnd, UInt32 msg, IntPtr wParam, IntPtr lParam)
at Avalonia.Win32.WindowImpl.WndProcMessageHandler(IntPtr hWnd, UInt32 msg, IntPtr wParam, IntPtr lParam)
at Windows.Win32.PInvoke.DispatchMessage(MSG* lpMsg)
at Windows.Win32.PInvoke.DispatchMessage(MSG* lpMsg)
at System.Windows.Forms.Application.LightThreadContext.FPushMessageLoop(msoloop uReason)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(msoloop reason, ApplicationContext context)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(msoloop reason, ApplicationContext context)
at System.Windows.Forms.Form.ShowDialog(IWin32Window owner)
at Devolutions.RemoteDesktopManager.Managers.ActionManager.EditConnection(ConnectionEngine engine, IConnectionSource source)
at Devolutions.RemoteDesktopManager.Managers.SessionMenuManager.MnuEditConnection_Click(Object sender, EventArgs e)
at DevExpress.XtraBars.BarItemLink.OnLinkClick()
at DevExpress.XtraBars.BarButtonItemLink.OnLinkAction(BarLinkAction action, Object actionArgs)
at DevExpress.XtraBars.ViewInfo.BarSelectionInfo.UnPressLink(BarItemLink link)
at DevExpress.XtraBars.Controls.CustomLinksControl.OnMouseUp(MouseEventArgs e)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at DevExpress.XtraBars.Controls.CustomControl.WndProc(Message& msg)
at System.Windows.Forms.NativeWindow.Callback(HWND hWnd, MessageId msg, WPARAM wparam, LPARAM lparam)
at Windows.Win32.PInvoke.DispatchMessage(MSG* lpMsg)
at System.Windows.Forms.Application.LightThreadContext.FPushMessageLoop(msoloop uReason)
at System.Windows.Forms.Application.LightThreadContext.RunMessageLoop(msoloop reason, Boolean fullModal)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(msoloop reason, ApplicationContext context)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(msoloop reason, ApplicationContext context)
at Devolutions.RemoteDesktopManager.Program.Main(String[] args)

We use version 2025.3.17.0 or 2025.3.20.0 as RDM; the behavior is identical in both versions.

Best regards
Alex