You must login via the Docker client with your login credentials before you can download the images:
docker login https://release.onegini.com
Then pull the latest images:
docker pull release.onegini.com/<customer-name>/token-server-<customer-name>:<version>
NOTE: If you did not receive login credentials, please contact Onegini support.
The second way is to import the Docker image from a tarball. Use this option when the Docker host cannot connect to the internet.
docker load < /path/to/token-server-<customer-name>-<version>.tar