We are unable to send some attachments with emails. Very small attachments e.g. 40b seem to be able to be sent without a problem. However some PDF files (e.g. 130kb) or some Word doc (e.g. 150kb) are not able to be sent. Some are sent and at other time some are not sent. We are not getting any undeliverable notices and nothing is stuck in a queue on the server.
We are using SBS 2003 R2