Ronald,

If you check out the CAT sample  projects that were installed with the SDK it looks like they recommend using a 'While True' loop for the application entry point that should capture a failed login and allow you to pop-up a dialog for a retry.  If the client successfully loads then that called routine returns a value that you can test to exit that endless loop.  My guess is that a failed client login will throw an exception that you can trap in this entry point routine.

Here is a snippet of from one of the CAT sample projects;

    ''' <summary>
    ''' The main entry point for the application.
    ''' </summary>
    Shared Sub Main(args As String())
        Dim strCommands As String = ""
        For i As Integer = 0 To args.Length - 1
            If i > 0 Then
                strCommands += " "
            End If
            strCommands += args(i)
        Next

        While True
            Try
                If MainHandler(args) Then
                    Exit While
                End If
            Catch e As Exception
                Dim result As DialogResult = MessageBox.Show(e.Message & ", Retry?", "Error", MessageBoxButtons.YesNo)
                If result = DialogResult.No Then
                    Exit While
                End If
            End Try
        End While
    End Sub

It also looks like you can specifically trap Laserfiche CAT exceptions in the above code with something like this;

Catch lfex As Laserfiche.ClientAutomation.ClientAutomationException