I am experiencing issues with sending email with attached (1 page) documents, if the attached documents (typically .doc & .prf) have multiple links. I know this because if I send email from my gmail.com account to a colleague who uses shaw.ca (cable ISP), they receive my email tagged "Shaw suspected junk email". However, if I send an email to the same account with the same (1-page) document (both .doc & .pdf versions) with the HTML links stripped-out, the "suspected junk email" tag does not appear ... so the problem seems to be related to the links somehow.

I spoke with Shaw technical support and forwarded the same email with the same document attached (both original .doc and .pdf) and they called me back to say that they also saw a "suspected junk email" tag, but could not see any obvious issue with either the email or the attached documents. They also told me that Shaw uses Zimbra for spam and junk mail filtering ... but were unable to tell me if some specific URL was causing a problem, or if it was the number of links.

The subject document is a one page summary, with various links so that the reader can find more information if wanted. There is nothing remotely spammy or junky about either the email message (just three lines) or the document.

This is massively frustrating, because I am being forced to send out a one page summary
WITHOUT any links. The recipients of this document are accustomed to seeing links for further information ... but Zimbra does not allow for this.

Can anyone help me understand what junk mail / spam mail rules may be triggering my email to be a false positive for junk mail?!?

Thanks in advance to any and all kind souls who can shed light on this issue.