I am using this code (below) and it is giving me an error (Variable not
defined) with the letter A of Serie A highlighted. Any help please?

This is the code:

Option Explicit
Dim nextSecond

Sub startFlashing()
flashCell
End Sub

Sub stopFlashing()
On Error Resume Next
Application.OnTime nextSecond, "flashCell", , False
End Sub

Sub flashCell()
nextSecond = Now + TimeValue("00:00:01")
Application.OnTime nextSecond, "flashCell"


If Range("AN6").Interior.ColorIndex = 3 Then
Serie A.Range("AN6").Interior.ColorIndex = 41
Serie A.Range("AN6").Value = "Light Blue"


ElseIf Range("AN6").Interior.ColorIndex = 41 Then
Serie A.Range("AN6").Interior.ColorIndex = 3
Serie A.Range("AN6").Value = "Pink"

End If

If Range("AW6").Interior.ColorIndex = 3 Then
Serie A.Range("AW6").Interior.ColorIndex = 41
Serie A.Range("AW6").Value = "Light Blue"


ElseIf Range("AW6").Interior.ColorIndex = 41 Then
Serie A.Range("AW6").Interior.ColorIndex = 3
Serie A.Range("AW6").Value = "Pink"


End If
End Sub

Thanks for your help.