ISP: Ecotel Communication AG

Location: Düsseldorf, Germany

OS: Windows 10 Pro, Version 1809, Build 17763.475

Frequency: every time

Maybe this part of the logfile might help you to find out what's going on:

ERROR: Der Remoteserver hat einen Fehler zurückgegeben: (403) Unzulässig. (System.Net.WebResponse EndGetResponse(System.IAsyncResult) in System) []
bei System.Net.HttpWebRequest.EndGetResponse(IAsyncResult asyncResult)
bei MS.Internal.WpfWebRequestHelper.EndGetResponse(WebRequest request, IAsyncResult ar)
bei System.Windows.Navigation.NavigationService.HandleWebResponse(IAsyncResult ar)
bei System.Windows.Navigation.NavigationService.<>c__DisplayClass106_0.<HandleWebResponseOnRightDispatcher>b__0(Object unused)
bei System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
bei System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)

ISP: Spectrum (Time Warner)
Location: Dallas, TX
OS: Windows 10 Enterprise LTSB Version 1607 (OS Build 14393.2897)
Frequency: Every time

ISP: ANRC Services GmbH

Ubicacion: Alicante, Spain.

SO: Windows 10 64-bit

Frecuencia: Cada vez

ISP: Local ISP (Prowifi) connected to the network of UPC Czech Republic

Location: Velký Týnec, Czech Republic

OS: Windows 10 (Pro) 64-bit version 1809 (build 17763.529)

Frequency: Everytime the app is opened

Log message:

26.5.2019 20:07:16> ERROR: The remote server returned an error: (403) Forbidden. (System.Net.WebResponse EndGetResponse(System.IAsyncResult) in System) []
   at System.Net.HttpWebRequest.EndGetResponse(IAsyncResult asyncResult)
   at MS.Internal.WpfWebRequestHelper.EndGetResponse(WebRequest request, IAsyncResult ar)
   at System.Windows.Navigation.NavigationService.HandleWebResponse(IAsyncResult ar)
   at System.Windows.Navigation.NavigationService.<>c__DisplayClass106_0.<HandleWebResponseOnRightDispatcher>b__0(Object unused)
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)

ISP: LATROBE University

Location: Bendigo, Victoria, Australia

OS: Win 10 Pro 64-bit version 1809 build 17763.503

Frequency: On Application Startup