Set up DMARC and see who's sending email using your brand's domain.

Beware of Cloudfront URLs in email

Last week we were troubleshooting a problem with a customer. For some reason, no matter what we tried, their emails were going directly to the spam folder in Yahoo. I tried replicating the email, from name, subject and everything else but each time it went to the Inbox. After lots of tests, we identified one difference: After we moved the image to their own domain, it went right to the inbox.

So, what does this mean? #

The issue is nothing new. When it comes to publicly used domains, there is a high chance of spammers also using these domains, which can end up on uri blacklists. Similar problems have happened with and Tinyurl. The usual troubleshooting is to head over to sites like SURBL and URIBL to check if the domain is listed. In this case however, is no where to be found. It seems that Yahoo has some of their own internal rules for this domain.

How to prevent this from happening #

If you use CDN services (like Coundfront) or URL shortener services (like we recommend creating CNAME records so you can use your own domain. also offers a Pro service where you can use your own domain. By using your own domain, you can control your own reputation when it comes to blacklists (if it is domain based). Of course, if you act like a spammer, you’ll most likely end up on those lists as well.

Has anyone else noticed issues with Cloudfront? I’m interested to hear other examples so we can help other customers with delivery.

Chris Nagele

Chris Nagele

Love to travel with the wife and kids. Wannabe race car driver. Not so healthy obsession with Building Science.