PDF attachment is not good when sending as mail in .Net

My application send mail with PDF attachment to different mail ids. I have problem when i send PDF with big size. The PD开发者_如何学JAVAF doesn't look good. The color inside PDF is getting changed.

Does anyone come across this type of problem

The mail server is not limited with any message size

The mail transfer alone shouldn't change the content of the PDF. Are you generating the PDF yourself, maybe there is where the error happens. Otherwise it could be some third party tool (firewall maybe) that modifies the attachement.

A workaround you could try is to zip the PDF before you send it and send the zipped document.

it worked after changing the encoding type from QuotedPrintable to base64