When accessing a Docker repository through Artifactory, the repository URL must be prefixed with api/docker in the path.
You can copy the full URL from the UI using Set Me Up when the repository is selected in the Tree Browser.
For example, if you are using Artifactory standalone or as a local service, you would access your Docker repositories using the following URL:
http://localhost:8081/artifactory/api/docker/<repository key>
Also, the domain of your Docker repository must be expressed as an explicit IP address. The only exception is when working locally, you can use the localhost domain name as the proxy pass.