Implementing Amazon Cloudfront, plugin prepends domain to image urls?

I’ve configured everything in the plugin. I’ve tested the images on the CDN and they work fine.

However, when I enable the plugin, Super Cache starts using this url https://chicagophoenix.com/d18l6vcvyycasf.cloudfront.net/wp-content/blogs.dir/2/files/2012/07/cplogo-siteupper-fa12d.png

for images, instead of the CNAME (https://cdn.engn.us/wp-content/blogs.dir/2/files/2012/07/cplogo-siteupper-fa12d.png) or direct cloudfront url (https://d18l6vcvyycasf.cloudfront.net/wp-content/blogs.dir/2/files/2012/07/cplogo-siteupper-fa12d.png)

https://www.ads-software.com/extend/plugins/wp-super-cache/