No Domain Specified error

I get a "No Domain Specified" error when trying to send an email with an
attachment using Indy 10 for D6.  I'm not sure where I'm supposed to supply
the domain name or if it's referencing the domain of the Sender or
Recipient.

Here's my code:

  with IdMsgSend do
  begin
    From.Text := OwnerTbl.FieldbyName('ABBREVIATION').AsString;
    ReplyTo.EMailAddresses := OwnerTbl.FieldbyName('EMAIL').AsString;
    Recipients.EMailAddresses := 'support@swanbergcomputing.com';
    Subject := 'SOS BASEBALL DATA';
  end;

   IdAttachmentFile.
   TIdAttachmentFile.Create(IdMsgSend.MessageParts, 'C:\BASEBALL.ZIP');
   SMTP.Connect;
  try
    SMTP.Send(IdMsgSend);
  finally
    SMTP.Disconnect;
  end;