Sending email using a query based on a value from a subform produces error

access 2010 vba

I'm trying to send an email in the body of outlook. adding the results from a query.
The query is based on an ID in the subform.

the code is working fine on just a regular query. without "WHERE" clause.

Set MyDB = CurrentDb
Set rst = MyDB.OpenRecordset("Query_FOR_HTML")

But when using the following query. I get an error " too few parameters expected 1"
Trying to use value from subform field  RBP_MASTER_ID


SELECT dbo_t_pricing_escalation_detail.RBP_MASTER_ID, dbo_t_pricing_escalation_detail.SKU, dbo_t_pricing_escalation_detail.QTY, dbo_t_pricing_escalation_detail.TARGET_PRICE, dbo_t_pricing_escalation_detail.TARGET_GP
FROM dbo_t_pricing_escalation_detail
WHERE (((dbo_t_pricing_escalation_detail.RBP_MASTER_ID)=[Forms]![Main]![dbo_t_pricing_escalation_detail_subform]![RBP_MASTER_ID]));

Dim MyDB As DAO.Database
Dim rst As DAO.Recordset
  
Set MyDB = CurrentDb
Set rst = MyDB.OpenRecordset("Query_FOR_HTML")




  
With rst
  Do While Not .EOF
    Mailbody = Mailbody & ![RBP_MASTER_ID] & " | " &   ![Sku] & " | " & ![Qty] & " | " & ![TARGET_PRICE] & vbCrLf
      .MoveNext
  Loop
End With
  

Dim appOutLook As Outlook.Application
   Dim MailOutLook As Outlook.MailItem
   Dim strPath As String
   Dim strFileName As String
   Set appOutLook = CreateObject("Outlook.Application")
   Set MailOutLook = appOutLook.CreateItem(olMailItem)
   
   
   
   With MailOutLook
     .BodyFormat = olFormatRichText
     .To = "xxxell@xxxxxger.com"
     '.CC = ""
     '.bcc = ""
     .Subject = "Testing" & Date
     .Body = "UK Backorder Report " & vbCrLf & " " & vbCrLf & Mailbody
            
     .Send
End With
rst.Close
Set rst = Nothing
  
  MsgBox "done"

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