I cannot add any TM anymore to new and existing projects, TMs are deactivated. Here is the error message generated:
 
   Value cannot be null.
Parameter name: serviceType
   
     System.ArgumentNullException, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
     serviceType
     
     SimpleInjector
     -2147467261
      c__DisplayClass3_0. b__0(IObjectResolver r)
   at System.Linq.Enumerable.FirstOrDefault[TSource](IEnumerable`1 source, Func`2 predicate)
   at Sdl.Desktop.Platform.Implementation.ObjectResolverComposer.CreateObject(Type objectType, XElement attributeElement)
   at Sdl.Core.PluginFramework.Implementation.Extension.CreateInstance()
   at Sdl.Core.PluginFramework.ObjectRegistry`2.CreateObjects()
   at Sdl.LanguagePlatform.TranslationMemoryApi.TranslationProviderManager.GetTranslationProviderFactories()
   at Sdl.ProjectApi.TranslationProviderItem.GetTranslationMethod()
   at Sdl.ProjectApi.TranslationProviderItem.IsMachineTranslation()
   at Sdl.TranslationStudio.Common.TranslationMemory.AutoTranslateEnabler.SignalIfAutoTranslateShouldBeEnabled(ITranslationProviderItem currentProvider)
   at Sdl.TranslationStudio.Common.TranslationMemory.TranslationMemoriesControl.pluginContextMenuStripItem_Click(Object sender, EventArgs e)
   at System.Windows.Forms.ToolStripItem.RaiseEvent(Object key, EventArgs e)
   at System.Windows.Forms.ToolStripMenuItem.OnClick(EventArgs e)
   at System.Windows.Forms.ToolStripItem.HandleClick(EventArgs e)
   at System.Windows.Forms.ToolStripItem.HandleMouseUp(MouseEventArgs e)
   at System.Windows.Forms.ToolStripItem.FireEventInteractive(EventArgs e, ToolStripItemEventType met)
   at System.Windows.Forms.ToolStripItem.FireEvent(EventArgs e, ToolStripItemEventType met)
   at System.Windows.Forms.ToolStrip.OnMouseUp(MouseEventArgs mea)
   at System.Windows.Forms.ToolStripDropDown.OnMouseUp(MouseEventArgs mea)
   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.ToolStrip.WndProc(Message& m)
   at System.Windows.Forms.ToolStripDropDown.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, Int32 msg, IntPtr wparam, IntPtr lparam)]]>
   
   
     SDL Trados Studio
     Studio16
     16.1.8.4404
     Microsoft Windows 10 Pro
     NULL
     1031
     1252
     DESKTOP-POPB42E\td translations
     4.0.30319.42000
     DESKTOP-POPB42E
     True
     33509088 MB
   
 
 

What was done by Jerzy Czopik:
•    Restarting Studio
•    Restarting the PC
•    Using Windows restore point
•    Deleting the usual files from roaming/appdata
•    Resetting window layout
•    Using a different, new user profile
•    Using a completely freshly imported template from the installation folder of Studio
•    Removing the translationmemoryrepository.xml
•    Reverting to the version 16.1.5 from May 2021

Nothing helped, the error message is still there and Jerzy has no further ideas what to do. Any help will be greatly appreciated as I am unable to work with Studio, which is more than annoying! Thanks