Формат успешного ответа:
код - 201
тело ответа:
{
"payment_ref": "референс созданного платежа"
"payment_pack_ref": "запакованный референс созданного платежа"
}

Private Sub PostZapros()
On Error GoTo lbl
Dim XMLHTTP As New MSXML2.XMLHTTP60
Dim sHTTP As New WinHttp.WinHttpRequest
Dim strQuery As String, myUrl As String
  
  strQuery = "{" _
    & """document_number"":""autoclient""," _
    & """recipient_account"":""" & Me.idKlienti.Column(2) & """," _
    & """recipient_nceo"":""" & Me.idKlienti.Column(3) & """," _
    & """payment_naming"":""" & Me.idKlienti.Column(1) & """," _
    & """payment_amount"":""" & Me.payment_amount & """," _
    & """recipient_ifi"":""" & Me.idKlienti.Column(4) & """," _
    & """payment_destination"":""" & Me.payment_destination & """," _
    & """payer_account"":""" & Me.idMoiFirmi.Column(2) & """" _
    & "}"
  'Debug.Print strQuery


  myUrl = "https://acp.privatbank.ua/api/proxy/payment/create_pred"
  
  With sHTTP 'XMLHTTP тоже работает
    .Open "POST", myUrl, False
    .setRequestHeader "User-Agent", "autoklient"
    .setRequestHeader "id", idKlienta
    .setRequestHeader "token", tokenKlienta
    .setRequestHeader "Content-Type", " application/json;charset=UTF-8"
    .send (strQuery)
    Debug.Print .Status
    Debug.Print .ResponseText
  End With
    
lbl:
  If Err.Number <> 0 Then _
    Debug.Print Err.Number, Err.Description
  
  On Error Resume Next
  
  Debug.Print "sHTTP.Status: ", sHTTP.Status
  Debug.Print "XMLHTTP.Status:", XMLHTTP.Status
  
  Set sHTTP = Nothing
  Set XMLHTTP = Nothing

End Sub

    .setRequestHeader "Content-Type:", "application/json"

201
-2147023783   Символ Юникода не имеет сопоставления в конечной многобайтовой кодовой странице.