Button not showing on sent emails but does in Preview and Test

Hi All,

I'm using custom coded email to send emails and there's a button with a link in it. It shows up fine in Dreamweaver, and also on Preview and the Test email, but when I send the actual email it doesn't show. 

If you look here https://conta.cc/36gcjk4

then look at the "Visit" and "Live Internet Bidding" link half-way down, the "-->" and link down work in the actual email but do in Preview and the Test email. 

Thanks for any help.

Jason