A family of Microsoft word processing software products for creating web, email, and print documents.
You are sending the word document as an attachment, not using it in a mail merge, correct? It definitely will not work in a mail merge - the recipient will get it as a PDF image in the message.
Sending the document as an attachment is working here - i can open the embedded pdf. Security settings on the recipients computer could prevent it from opening, but the recipient should receive a warning message.