VBA exit before end - vba

Question

The code: a commandutton code with two parts, The first part of it sort the cells, and second part is recoloring the sorted cells.
The problem: the macro exit after the first, without doing the recoloring. If I commented the first part, the code does the recoloring.
Any idea, what could be the problem?
Private Sub CommandButton1_Click()
Application.ScreenUpdating = False
Dim i As Integer
Dim WName As String
''First Part
WName = ActiveWorkbook.ActiveSheet.Name
Range("B2:B21").Select
ActiveWorkbook.Worksheets(WName).Sort.SortFields.Clear
ActiveWorkbook.Worksheets(WName).Sort.SortFields.Add Key:=Range("B2:B21"), SortOn:=xlSortOnValues, Order:=xlAscending, DataOption:=xlSortNormal
With ActiveWorkbook.Worksheets(WName).Sort
.SetRange Range("B2:B21")
.Header = xlGuess
.MatchCase = False
.Orientation = xlTopToBottom
.SortMethod = xlPinYin
.Apply
End With
''Second Part
For i = 2 To 21
If i Mod 2 = 0 Then
Cells(i, 2).Select
With Selection.Interior
.Pattern = xlSolid
.PatternColorIndex = xlAutomatic
.ThemeColor = xlThemeColorAccent3
.TintAndShade = 0.799981688894314
.PatternTintAndShade = 0
End With
Else
Cells(i, 2).Select
With Selection.Interior
.Pattern = xlSolid
.PatternColorIndex = xlAutomatic
.ThemeColor = xlThemeColorAccent3
.TintAndShade = 0.399975585192419
.PatternTintAndShade = 0
End With
End If
Next i
End Sub