When you see the error message, “One or more of the CNAMEs you provided are already associated with a different resource,” it usually means the domain name you’re trying to add is already linked to another CloudFront distribution. This could be in your account or possibly in a different AWS account.
To fix this, you have a couple of options:
If you have access to the original distribution that’s using the domain, you can move the domain from that distribution to your new one. This involves setting up your new distribution correctly, finding the current distribution that has the domain, and transferring the domain to your new setup. You can do this between different distributions or even different accounts.
If you don’t have access to the original distribution, but you own the domain through Amazon Route 53, it likely means the domain is connected to an account you no longer manage. In this case, the best step is to contact AWS Support. They can help verify your ownership of the domain and release the connection to the old distribution so you can use it with your new one.
Since you’ve already created a support case, that’s the right move. You can add more information or check the status of your case through the AWS Support Center at https://console.aws.amazon.com/support/. If you find you’re waiting too long for a reply, consider reviewing your AWS Support plan options. Higher-tier plans usually offer faster response times, which can be helpful if you need a quick resolution.
AWS Support has the tools needed to confirm domain ownership and can release any CNAME associations that are blocking your setup. This is especially useful when the domain is tied to an inaccessible distribution.
For more details, you can visit the official guide on moving an alternate domain name in Amazon CloudFront at https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/alternate-domain-names-move.html.