While trying to istall Trados studio 2021, the above message appears, as well as the following:

<SDLErrorDetails time="8/7/2021 2:08:34 μμ">
<ErrorMessage>Δεν έχει οριστεί αναφορά αντικειμένου σε μια παρουσία αντικειμένου.</ErrorMessage>
<Exception>
<Type>System.NullReferenceException, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</Type>
<HelpLink />
<Source>Sdl.TranslationStudio.LanguageCloud</Source>
<HResult>-2147467261</HResult>
<StackTrace><![CDATA[ σε Sdl.TranslationStudio.LanguageCloud.Subscription.DeviceInformationRetriever.GetComputerSid()
σε Sdl.TranslationStudio.LanguageCloud.Subscription.DeviceIdentifier.GetStudioInstanceId()
σε Sdl.TranslationStudio.LanguageCloud.Subscription.SubscriptionLicense.LoadSubscriptionFromLocalStore()
σε Sdl.TranslationStudio.Common.Licencing.LicensingService.ShouldShowLicenseManager()
σε Sdl.TranslationStudio.Common.Licencing.LicensingService.StartupLicenseCheck()
σε Sdl.Desktop.Platform.Implementation.Studio.Run(ISplashScreen splashScreen, IEventAggregator eventAggregator, IPluginLoaderService pluginLoaderService, ICommandLineParsingService commandLineParsingService)
σε Sdl.TranslationStudio.Application.Launcher.RunApplication()]]></StackTrace>

Any ideas on how this problem can be solved?