run time error 462 the remote server machine does not exist

Hi All

When i run the code below for the first time i receive the error as per the title. When i run it a second time it run through correctly. I have read a bit on it and see that it could be late bindings or Implicit references but i don't really see if and where this would apply in the code below.
The code breaks on this line

 ActiveDocument.MailMerge.Fields.Add Range:=WdDoc.Bookmarks(cell.Offset(0, 2).Value).Range, Name:=txt & cell.Offset(0, 3).Value

Select allOpen in new window

Sub DoMerge()
Dim appWd As Word.Application
Dim WdDoc As Word.Document
Dim strBookFullName As String
Dim cell As Excel.Range
'Dim wdFind As Object
Dim txt As String
'Dim MyDoc As String

strBookFullName = ActiveWorkbook.FullName

Set appWd = CreateObject("Word.Application")
appWd.Visible = True

With appWd
    Set WdDoc = appWd.Documents.Open("C:\Users\Elmo\Documents\Aaron\2nd Project 2017\WorkingOn\VendorRebateClientDoc4March17_2.docx")
    WdDoc.Activate
    WdDoc.MailMerge.OpenDataSource Name:=(strBookFullName), _
    ReadOnly:=True, LinkToSource:=0, AddToRecentFiles:=False, _
    PasswordDocument:="", PasswordTemplate:="", WritePasswordDocument:="", _
    WritePasswordTemplate:="", Revert:=False, Format:=wdOpenFormatAuto, _
    Connection:="", SQLStatement:="SELECT * FROM `MergeRange`", SQLStatement1:=""

'Set wdFind = appWd.Selection.Find
    'finds text in word doc and replace with merge field
    For Each cell In Range("MergeText")
        
        'wdFind.Text = cell.Value
        
        
        'MyDoc = WdDoc.Range.Text
            txt = cell.Offset(0, 1).Value
            ActiveDocument.MailMerge.Fields.Add Range:=WdDoc.Bookmarks(cell.Offset(0, 2).Value).Range, Name:=txt & cell.Offset(0, 3).Value
    Next cell
    
    .ActiveDocument.MailMerge.Execute
    .ActiveDocument.SaveAs "C:\Users\Elmo\Documents\Aaron\From Client\Output\test2.docx"
    
End With

End Sub

Select allOpen in new window

Thanks in advance
Elmo