vba Excel data Validation error 'Application-defined or object-defined error' I've read loads of similar questions and answers, but keep getting error.

What I do is I export query via

DoCmd.TransferSpreadsheet acExport, 8, "blabla", outputFile, True


Then I'm attempting to add validation to a range in my new excel file.

Here I get an error on setting AlertStyle:=xlValidAlertStop, Operator:=xlBetween, 

(no errors without them, but no validation is set as well, obviously)

[Application-defined or object-defined error ]

Running same code from Excel - cause no issues!

Sub ApplyExcelFormating(ByVal myFile As String, ByVal mySpreadsheet As String)

    Dim myValidationList(1) As String
    myValidationList(0) = "YES"
    myValidationList(1) = "OK"

    Dim XL As Object, WB As Object, WKS As Object
    Set XL = CreateObject("Excel.Application")
    XL.Visible = True
    XL.DisplayAlerts = True
    Set WB = XL.Workbooks.Open(myFile)
    WB.Activate
    Set WKS = WB.worksheets(mySpreadsheet)

    Dim lastrow As Integer
    lastrow = WKS.UsedRange.Rows.Count


    WKS.Range("K2:K" &amp; lastrow).Activate
    WKS.Range("K2:K" &amp; lastrow).Select


Only these two cause error:

    'AlertStyle:=xlValidAlertStop, Operator:=xlBetween,
    With WKS.Range("K2:K" &amp; lastrow).Validation
    .Delete
    .Add Type:=xlValidateList, AlertStyle:=xlValidAlertStop, Operator:=xlBetween, Formula1:=Join(myValidationList, ",")
    .IgnoreBlank = True
    .InCellDropdown = True
    .InputTitle = ""
    .ErrorTitle = ""
    .InputMessage = ""
    .ErrorMessage = ""
    .ShowInput = True
    .ShowError = True
    End With

    WB.Save
    XL.Workbooks.Close
    XL.Visible = True 
End Sub
I found a way around the issues i had, related to Excel Data Validation setup from Access via VBA. 
Here:
https://msdn.microsoft.com/en-us/library/office/ff840715.aspx

For some weird reason, VBA would not set data validation based on property names.
E.g. if I use Type:=xlValidateList - nothing changes in the spreadsheet.
While the below does the job:

... .Validation.Add Type:=3, Operator:=2, AlertStyle:=2, Formula1:="YES,OK"