If you select Port as the Reverse Proxy Method, when configuring a Docker Repository, you will need to set the Registry Port in the Docker Repository Configuration Advanced tab. Together with the Public Server Name, this is the port the Docker client will use to pull images from and push images to the repository. Note that in order for all of your Docker repositories to be included in your reverse proxy configuration, first you need to set the port for each Docker repository defined in your system, and only then generate the reverse proxy configuration. Note also that each repository must be bound to a unique port
We recommend creating a Virtual Docker Repository which aggregates all of your other Docker repositories, and use that to pull and push images. This way you only need to set up the NGINX configuration for that virtual repository.
Docker Settings in HTTP Settings
Corresponding HTTP Settings in Docker Repository Advanced Configuration