VBA Spell Check

Hi!

I have an excel spreadsheet with around 10,000 cells in a single column which all contain 200-300 words of text and need spell checking. I am very new to VBA and Macros so found the following code online and simply pasted it into the Visual Basic Editor tool on Excel for Mac.

Sub ColorMispelledCells()
For Each cl In ActiveSheet.UsedRange
If Not Application.CheckSpelling(Word:=cl.Text) Then _
cl.Interior.ColorIndex = 28
Next cl
End Sub

When I hit run it returns a "Run-time error '13': Type mismatch" message.

Could anyone help/tell me what I am doing wrong?

Thanks!