Charts: ScaleResolutionFailure(message: "Scale domain configuration doesn't match encoded value type")

            Chart { 
                
                ForEach(viewModel.chartDBdata) { index in

                    LineMark(x: .value("Seq", index.dataSeqInSwing), y: .value("Value",index.value) )
                        .foregroundStyle(by: .value("itemType", index.itemType))

                }
            }
            .chartForegroundStyleScale([
                "angle": .red,
                "degree": .orange,
                "grip1": .yellow,
                "grip2": .blue
            ])
            .frame(height: 300)
            .padding()
           .onAppear{ 
                viewModel.findContact()
                print("Chart_OnAppear after vm.findcontact")
            }
            .tabItem {
            Image(systemName: "2.circle")
            Text("data base")
        }.tag(2)

Charts: ScaleResolutionFailure(message: "Scale domain configuration doesn't match encoded value type")

<0x10190ebd0> Gesture: System gesture gate timed out.

immediately after ForEach looping completion,

error message above is shown.

why does this happen ?