The limit on any one message is 30MB, and that includes attachments after encoding. Please note that a binary file such as a Word document will increase in size by 33% as a result of the encoding necessary for attachment to email. Therefore, a file of 10MB in size will increase to more than 13MB after encoding. If you have an attachment that exceeds the 30MB limit, please try compressing the file – files can often be compressed to a tenth of their original size using standard (WinZip, WinRAR, etc) compression utilities.
Please also keep in mind that we have no control over the file size limit that your recipients will accept. Although our server may accept an outbound 30MB attachment from you for delivery, your recipient’s mail server might have a limit of, say, 20MB, and in that case, the message would bounce back to you.