hyperlinks not working when downloading PDF from email

So I am using Illustrator and I have a couple of hyperlinks in the document. I made them transparent, so the layout looks nicer. The links work when I save it as a copy to a PDF from Illustrator and then I attach it to an email and it works when you open the document from the email. But when the PDF is downloaded from the email, some of the hyperlinks don't click, and some parts of the URL change. Any advice on how to fix this? Thank you!