SMTP Web.Email attachement problem

I have I believe setup everything to work and it does. However, any one of my attachments over 64k in size are stripped down to 64k and left empty/corrupt but anything under 64k is perfect. I checked with the mail team here at my work to see if any limitation was set on the file attachment smtp relay and there is a 20 meg cap.

I tried to search around for a setting somewhere that would be limiting this. Any ideas? I need to get this solved ASAP. So thanks in advance!

SteveOk, I have nailed it down to one of my web cluster servers. One server sends out just fine but the other one chops the attachment off at 64k if the file size exceeds. Does anyone know why this is happening on one versus the other?
Just curious if anyone has ANY idea where to look. I'm not using the buildin (localhost) smtp that came with IIS. I have the service stopped. Where else can I look?