Telekom Mail Abruf funktioniert nicht

Hallo,
seit gestern kann eM Client keine Verbindung zum Telekom Servier aufbauen.

Meine Einstellungen wurden nicht verändert -
kann es wegen der Umstellung seitens Telekom auf TLS 1.2 / 1.3 sein ?

Folgende Einstellungen habe ich :

IMAP : Port 993 - SSL/TLS auf bestimmten Ports verwenden (Legacy)
SMPT : Port 587 - SSL/TLS auf bestimmten Ports verwenden (Legacy)

Wie gesagt bis vorgestern klappte noch alles.
Mit einem anderen Provider geht eM Client noch.

Bei der Telekom kann ich mich einloggen und Mail senden und empfangen, scheinbar liegt es also bei eM Client.

Viren Programm deaktiviert + Firewall - keine Besserung

Voran kann es liegen ?

Gruß
Andreas

Anbei der Fehlerbericht :

10:20:22 XXX@t-online.de IMAP Synchronisiere Ordnerliste
10:20:23 XXX@t-online.de [IMAP] MailClient.Accounts.ConnectionException: Authentication failed, see inner exception.
—> System.Security.Authentication.AuthenticationException: Authentication failed, see inner exception.
—> System.ComponentModel.Win32Exception (0x80090302): Die angeforderte Funktion wird nicht unterstützt.
— End of inner exception stack trace —
at System.Net.Security.SslStream.ForceAuthenticationAsync[TIOAdapter](TIOAdapter adapter, Boolean receiveFirst, Byte[] reAuthenticationData, Boolean isApm)
at MailClient.Imap.Base.Connection.<>c__DisplayClass82_0.<b__0>d.MoveNext()
— End of stack trace from previous location —
at MailClient.Imap.Base.TransportPipe.<>c__DisplayClass34_0.<b__0>d.MoveNext()
— End of stack trace from previous location —
at MailClient.Imap.Base.TransportPipe.UpgradeStreamAsync(Func2 callback) at MailClient.Imap.Base.Connection.ConnectAsync(Func2 getStream, CancellationToken cancellationToken)
at MailClient.Imap.Base.Connection.ConnectAsync(Func2 getStream, CancellationToken cancellationToken) at MailClient.Protocols.Imap.ConnectionPoolEntry.ConnectInternalAsync(CancellationToken cancellationToken) --- End of inner exception stack trace --- at MailClient.Protocols.Imap.ConnectionPoolEntry.ConnectInternalAsync(CancellationToken cancellationToken) at MailClient.Protocols.Imap.ConnectionPool.AcquireConnectionAsync(Folder mailFolder, Boolean noSelect) at MailClient.Protocols.Imap.ConnectionContext.CreateContextAsync(ImapAccount account) at MailClient.Protocols.Imap.ImapFolderSynchronizer.ListFoldersAsync(IListFoldersProgress progress, Folder homeFolder, CancellationToken cancellationToken) at MailClient.Protocols.Imap.ImapFolderSynchronizer.GetFolderList(IListFoldersProgress progress, Folder homeFolder, CancellationToken cancellationToken) at MailClient.Protocols.Common.FolderSynchronizer.<>c__DisplayClass16_0.<EnqueueGetFolderList>b__0(WorkerStatus status, CancellationToken cancellationToken) at MailClient.Protocols.Imap.ImapActionCommand.<>c__DisplayClass11_0.<.ctor>b__0(WorkerStatus ws, CancellationToken ct) at MailClient.Protocols.Imap.ImapActionCommand.ExecuteInternalSync(WorkerStatus status) at MailClient.Protocols.Imap.ImapActionCommand.Execute(WorkerStatus status) at MailClient.Commands.Command.Process(WorkerStatus status) --- End of stack trace from previous location --- at MailClient.Storage.Synchronization.FolderSynchronizerExtensions.SynchronizeSubfoldersAsync(IFolderSynchronizer synchronizer, Folder folder, SynchronizationPriority priority, CancellationToken cancellationToken) at MailClient.Protocols.Imap.ImapAccount.SynchronizeIntAsync(Boolean forced) at MailClient.Protocols.Common.SynchronizableMailAccount.<>c__DisplayClass7_0.<<SynchronizeAsync>b__0>d.MoveNext() IMAP_SERVER_TYPE = Dovecot EnqueuedStackTrace = at MailClient.Protocols.Common.FolderSynchronizer.EnqueueGetFolderList(Folder homeFolder, Action1 completed, Boolean prioritize)
at MailClient.Protocols.Common.FolderSynchronizer.GoOnlinePre()
at MailClient.Protocols.Imap.ImapFolderSynchronizer.GoOnlinePre()
at MailClient.Protocols.Imap.ImapAccount.GoOnlineInt()
at MailClient.Protocols.Common.AccountBase.ChangeOnlineState(Boolean online, OfflineReason offlineReason)
at MailClient.Protocols.Common.AccountBase.GoOnline()
at MailClient.Protocols.Common.AccountBase.RunIfOnline[T](Func1 actionIfOnline, Func1 actionIfOffline)
at MailClient.Protocols.Common.SynchronizableMailAccount.Synchronize(SynchronizationPriority priority)
at MailClient.Accounts.BindingAccountBase.Receive()
at MailClient.Accounts.AccountManager.ReceiveAllInternal(Boolean checkIncludeInGlobalOperations)
at MailClient.Accounts.AccountManager.SendAndReceiveAll(Boolean checkIncludeInGlobalOperations)
at MailClient.UI.Forms.formMain.sendReceiveAll()
at MailClient.UI.Forms.formMain.stripButton_Refresh_Click(Object sender, EventArgs e)
at System.Windows.Forms.Control.OnClick(EventArgs e)
at MailClient.Common.UI.Controls.ControlToolStrip.ControlToolStripButton.PerformClick()
at MailClient.Common.UI.Controls.ControlToolStrip.ControlToolStripButton.OnMouseUp(MouseEventArgs e)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
at System.Windows.Forms.ContainerControl.WndProc(Message& m)
at System.Windows.Forms.UserControl.WndProc(Message& m)
at MailClient.Common.UI.Controls.AutomationViewUserControl.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, WM msg, IntPtr wparam, IntPtr lparam)
at Interop.User32.DispatchMessageW(MSG& msg)
at System.Windows.Forms.Application.ComponentManager.Interop.Mso.IMsoComponentManager.FPushMessageLoop(UIntPtr dwComponentID, msoloop uReason, Void* pvLoopData)
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.Application.Run(ApplicationContext context)
at MailClient.Program.<>c.b__185_3()
at System.Windows.Forms.Control.InvokeMarshaledCallbackDo(ThreadMethodEntry tme)
at System.Windows.Forms.Control.InvokeMarshaledCallbackHelper(Object obj)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Windows.Forms.Control.InvokeMarshaledCallback(ThreadMethodEntry tme)
at System.Windows.Forms.Control.InvokeMarshaledCallbacks()
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
at System.Windows.Forms.ContainerControl.WndProc(Message& m)
at System.Windows.Forms.Form.WndProc(Message& m)
at MailClient.Common.UI.Forms.BaseForm.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, WM msg, IntPtr wparam, IntPtr lparam)
at Xilium.CefGlue.Interop.libcef.run_message_loop()
at MailClient.Program.Main(String[] args)
GUIStatus_Exception_Reported = True

Das sieht mit Win32Exeption nach einem lokalen Problem aus. Hast du kürzlich Windows aktualisiert?
Hier funktioniert der t-online Account (mit MacOS) weiterhin einwandfrei.