I have a client that is sending a 21MB ZIP file (a Quickbooks backup, compressed as a ZIP) to another client, and while they do receive the email, the attachment isn't included. As a test, I asked him to send it to my own email account and CC it to a Gmail account. It showed up on Gmail correctly, but my regular email account just received the email with no attachment. This eliminates the recipient's Outlook being the problem. The only setting that I could find that might impact this is "Attachments: Filter dangerous attachments" under Exim Configuration in WHM. I couldn't find anywhere that stated how a "dangerous attachment" is defined, but would this setting allow the email to go through without the attachment? If so, is there a way to modify it so that this attachment will go through, but not be so loose as to allow viruses and such through?