Chart VBA Coloring Lines

I have this code that colors the lines in my Line Chart


Sub ColorLines()

Application.ScreenUpdating = False

Set chrt = ActiveChart
'Here you want to put your own graph
vals = chrt.SeriesCollection(1).Values
'These are the values to determine later whether the line moves up or down. In this example, I just colored 1 seriescollection (= one line in your line graph), with an extra loop you'd do all lines.

It is very simple: When the lines goes up they turn black. When they go down they turn red.

The code work, but only if all cell in the series is filled. If one cells is blank the code error. I'm using #NA() in all cells that are blank, so the chart skip that cell and continue from the next cell's value.