Nullable Object must have a value" Error in Power Query in Azure Analysis Services

I am facing the following issue when I try to "import" in Power Query in Azure Analysis Services.

Feedback Type:
Frown (Error)

Timestamp:
2019-09-17T13:15:15.4896978Z

Local Time:
2019-09-17T15:15:15.4896978+02:00

Release:
August 2019

Product Version:
2.72.5556.542 (19.08) (x86)

Error Message:
Nullable object must have a value.

Stack Trace:
at System.ThrowHelper.ThrowInvalidOperationException(ExceptionResource resource)
at Microsoft.ProBI.MashupLibrary.Querying.QueriesEditorWindow.<CloseAndApplyAsync>d__65.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.ProBI.MashupLibrary.Querying.QueriesEditorWindow.<>c__DisplayClass64_0.<<CloseAndApply>b__0>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.ProBI.MashupLibrary.IExceptionHandlerExtensions.<HandleAsyncExceptions>d__0.MoveNext()

Stack Trace Message:
Nullable object must have a value.

Invocation Stack Trace:
at Microsoft.Mashup.Host.Document.ExceptionExtensions.GetCurrentInvocationStackTrace()
at Microsoft.Mashup.Client.UI.Shared.StackTraceInfo..ctor(String exceptionStackTrace, String invocationStackTrace, String exceptionMessage)
at Microsoft.Mashup.Client.UI.Shared.FeedbackErrorInfo..ctor(String message, Exception exception, Nullable`1 stackTraceInfo, String messageDetail)
at Microsoft.Mashup.Client.UI.Windows.UserFeedbackServicesBase.ReportException(IWindowHandle activeWindow, IUIHost uiHost, FeedbackPackageInfo feedbackPackageInfo, Exception e, Boolean useGDICapture)
at Microsoft.Mashup.Client.UI.Shared.UnexpectedExceptionHandler.<>c__DisplayClass14_0.<HandleException>b__0()
at Microsoft.Mashup.Host.Document.SynchronizationContextExtensions.<>c__DisplayClass0_1.<SendAndMarshalExceptions>b__0(Object null)
at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor)
at System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments)
at System.Delegate.DynamicInvokeImpl(Object[] args)
at System.Windows.Forms.Control.InvokeMarshaledCallbackDo(ThreadMethodEntry tme)
at System.Windows.Forms.Control.InvokeMarshaledCallbackHelper(Object obj)
at System.Windows.Forms.Control.InvokeMarshaledCallback(ThreadMethodEntry tme)
at System.Windows.Forms.Control.InvokeMarshaledCallbacks()
at System.Windows.Forms.Control.MarshaledInvoke(Control caller, Delegate method, Object[] args, Boolean synchronous)
at System.Windows.Forms.Control.Invoke(Delegate method, Object[] args)
at System.Windows.Forms.WindowsFormsSynchronizationContext.Send(SendOrPostCallback d, Object state)
at Microsoft.Mashup.Host.Document.SynchronizationContextExtensions.SendAndMarshalExceptions(SynchronizationContext context, Action callback)
at Microsoft.Mashup.Client.UI.Shared.UnexpectedExceptionHandler.HandleException(Exception e)
at Microsoft.Mashup.Client.UI.Shared.WebDialogs.WebDialogBase`1.DelayedInitializationExceptionHandler.HandleException(Exception e)
at Microsoft.ProBI.MashupLibrary.IExceptionHandlerExtensions.<HandleAsyncExceptions>d__0.MoveNext()
at System.Runtime.CompilerServices.AsyncVoidMethodBuilder.Start[TStateMachine](TStateMachine& stateMachine)
at Microsoft.ProBI.MashupLibrary.IExceptionHandlerExtensions.HandleAsyncExceptions(IExceptionHandler exceptionHandler, Func`1 asyncFunc)
at Microsoft.ProBI.MashupLibrary.Querying.QueriesEditorWindow.CloseAndApply(Boolean processAfterSave)
at Microsoft.ProBI.MashupLibrary.CommandUI.Commands.MashupCommandUICommandActionHandler.HandleCommand(UInt32 commandId)
at Microsoft.Mashup.Client.UI.Shared.UICommands.CommandActionHandlerBase.CommandAction(UInt32 commandId)
at Microsoft.ProBI.MashupLibrary.Toolbar.ToolbarCore.CommitCommand(String commandName)
at Microsoft.ProBI.MashupLibrary.Toolbar.ToolbarCore.ButtonClick(Object sender, EventArgs e)
at System.Windows.Forms.ToolStripItem.RaiseEvent(Object key, EventArgs e)
at System.Windows.Forms.ToolStripButton.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.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.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
at System.Windows.Forms.Application.ThreadContext.LocalModalMessageLoop(Form form)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
at System.Windows.Forms.Application.RunDialog(Form form)
at System.Windows.Forms.Form.ShowDialog(IWin32Window owner)
at Microsoft.Mashup.Client.UI.Windows.DialogWindowBase.ShowModal(IWindowHandle windowHandle)
at Microsoft.Mashup.Client.UI.Shared.WebDialogs.WebDialog.<>n__0(IWindowHandle owner)
at Microsoft.Mashup.Client.UI.Shared.WebDialogs.WebDialog.<>c__DisplayClass57_0.<ShowModal>b__0()
at Microsoft.Mashup.Client.UI.Shared.WindowManager.ShowModal[T](T dialog, Func`1 showModalFunction)
at Microsoft.Mashup.Client.UI.Shared.WebDialogs.WebDialog.ShowModal(IWindowHandle owner)
at Microsoft.ProBI.MashupLibrary.Querying.QueriesEditorWindowManager.StartEditor(Boolean isImport)
at Microsoft.ProBI.MashupLibrary.Querying.QueriesEditorWindowManager.OpenEditor(IEnumerable`1 originalDataSources, IEnumerable`1 existingTableNames, Queries queries, IEnumerable`1 queriesToEdit, Func`2 validateBeforeSave, Action`1 onEditorApply, Action onEditorCancelled, Boolean isImport)
at Microsoft.ProBI.MashupLibrary.API.OpenQueryEditorTask.PerformTask()
at Microsoft.ProBI.MashupLibrary.API.QueryTask`1.<PerformTaskInternal>b__36_0()
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)
at System.Windows.Threading.DispatcherOperation.InvokeImpl()
at System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(Object state)
at MS.Internal.CulturePreservingExecutionContext.CallbackWrapper(Object obj)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at MS.Internal.CulturePreservingExecutionContext.Run(CulturePreservingExecutionContext executionContext, ContextCallback callback, Object state)
at System.Windows.Threading.DispatcherOperation.Invoke()
at System.Windows.Threading.Dispatcher.ProcessQueue()
at System.Windows.Threading.Dispatcher.WndProcHook(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
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)
at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
at System.Windows.Forms.Application.ThreadContext.LocalModalMessageLoop(Form form)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
at System.Windows.Forms.Application.RunDialog(Form form)
at System.Windows.Forms.Form.ShowDialog(IWin32Window owner)
at Microsoft.AnalysisServices.Common.SandboxEditor.EditMappingsClicked(DataModelingTable table)
at Microsoft.AnalysisServices.VSHost.Integration.DataView.DataModelViewTableNode.<ExecCommandOnNode>b__17_7(SandboxEditor editor)
at Microsoft.AnalysisServices.VSHost.Integration.DataView.DataModelViewTabularNode.<>c__DisplayClass32_0.<RunIfEditorOpen>b__0(SandboxEditor editor)
at Microsoft.AnalysisServices.VSHost.Integration.DataView.DataModelViewTabularNode.RunIfEditorOpen[T](Func`2 editorAction, Func`1 otherwise)
at Microsoft.AnalysisServices.VSHost.Integration.DataView.DataModelViewTabularNode.RunIfEditorOpen(Action`1 editorAction)
at Microsoft.AnalysisServices.VSHost.Integration.DataView.DataModelViewTableNode.ExecCommandOnNode(Guid cmdGroup, UInt32 cmd, UInt32 nCmdexecopt, IntPtr pvaIn, IntPtr pvaOut)
at Microsoft.AnalysisServices.VSHost.Integration.DataView.DataModelViewNode.InternalExecCommand(Guid cmdGroup, UInt32 cmdId, UInt32 cmdExecOpt, IntPtr vaIn, IntPtr vaOut, CommandOrigin commandOrigin)
at Microsoft.AnalysisServices.VSHost.Integration.DataView.DataModelViewNode.Exec(Guid& guidCmdGroup, UInt32 nCmdId, UInt32 nCmdExecOpt, IntPtr pvaIn, IntPtr pvaOut)
at Microsoft.VisualStudio.Shell.Interop.IVsUIDataSource.Invoke(String verb, Object pvaIn, Object& pvaOut)
at Microsoft.Internal.VisualStudio.PlatformUI.DataSource.Invoke(String verb, Object pvaIn, Object& pvaOut)
at Microsoft.VisualStudio.PlatformUI.VsCommand.Execute(Object parameter)
at MS.Internal.Commands.CommandHelpers.CriticalExecuteCommandSource(ICommandSource commandSource, Boolean userInitiated)
at System.Windows.Controls.MenuItem.InvokeClickAfterRender(Object arg)
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)
at System.Windows.Threading.DispatcherOperation.InvokeImpl()
at System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(Object state)
at MS.Internal.CulturePreservingExecutionContext.CallbackWrapper(Object obj)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at MS.Internal.CulturePreservingExecutionContext.Run(CulturePreservingExecutionContext executionContext, ContextCallback callback, Object state)
at System.Windows.Threading.DispatcherOperation.Invoke()
at System.Windows.Threading.Dispatcher.ProcessQueue()
at System.Windows.Threading.Dispatcher.WndProcHook(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
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)
at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
at Microsoft.VisualStudio.PlatformUI.NativeMethods.DispatchMessage(MSG& lpmsg)
at Microsoft.VisualStudio.Platform.WindowManagement.WindowManagerService.<>c.<PushMessageLoopOnContextMenuTrackingComponent>b__226_1(Object sender, PreTranslateMessageEventArgs args)
at Microsoft.VisualStudio.PlatformUI.OleComponentSupport.OleComponent.FPreTranslateMessageCore(MSG[] pMsg)
at Microsoft.VisualStudio.PlatformUI.OleComponentSupport.OleComponent.<>c__DisplayClass23_0.<Microsoft.VisualStudio.OLE.Interop.IOleComponent.FPreTranslateMessage>b__0()
at Microsoft.VisualStudio.PlatformUI.OleComponentSupport.OleComponent.CallAndReturnOnException(Func`1 method, Int32 retValueOnException)
at Microsoft.VisualStudio.PlatformUI.OleComponentSupport.OleComponent.Microsoft.VisualStudio.OLE.Interop.IOleComponent.FPreTranslateMessage(MSG[] pMsg)
at Microsoft.VisualStudio.OLE.Interop.IOleComponentManager.FPushMessageLoop(UInt32 dwComponentID, UInt32 uReason, IntPtr pvLoopData)
at Microsoft.VisualStudio.Platform.WindowManagement.WindowManagerService.PushMessageLoopOnContextMenuTrackingComponent()
at Microsoft.VisualStudio.Shell.Interop.IVsUIShell.ShowContextMenu(UInt32 dwCompRole, Guid& rclsidActive, Int32 nMenuId, POINTS[] pos, IOleCommandTarget pCmdTrgtActive)
at Microsoft.AnalysisServices.VSHost.Integration.DataView.DataModelViewNode.ShowContextMenu(Int32 menuId, Guid menuGroup, POINTS points)
at Microsoft.AnalysisServices.VSHost.Integration.DataView.DataModelViewNode.DisplayContextMenu(IList`1 selectedNodes, IntPtr pointerToVariant)
at Microsoft.AnalysisServices.VSHost.Integration.DataView.DataModelViewNode.ExecCommandThatDependsOnSelectedNodes(Guid cmdGroup, UInt32 cmdId, UInt32 cmdExecOpt, IntPtr vaIn, IntPtr vaOut, CommandOrigin commandOrigin, IList`1 selectedNodes, Boolean& handled)
at Microsoft.AnalysisServices.VSHost.Integration.DataView.DataModelViewNode.InternalExecCommand(Guid cmdGroup, UInt32 cmdId, UInt32 cmdExecOpt, IntPtr vaIn, IntPtr vaOut, CommandOrigin commandOrigin)
at Microsoft.AnalysisServices.VSHost.Integration.DataView.DataModelViewNode.ExecCommand(UInt32 itemid, Guid& pguidCmdGroup, UInt32 nCmdID, UInt32 nCmdexecopt, IntPtr pvaIn, IntPtr pvaOut)

OS Version:
Microsoft Windows NT 10.0.17134.0 (x64 en-US)

CLR Version:
4.7 or later [Release Number = 461808]

Peak Virtual Memory:
1.7 GB

Private Memory:
590 MB

Peak Working Set:
658 MB

IE Version:
11.1006.17134.0

Telemetry Enabled:
True

DPI Scale:
150%