I was seeing the rather character dense and yet information sparse error from Docker:
Error response from daemon: manifest for graylog/graylog:latest not found: manifest unknown: manifest unknown
Yes, I was hacking around with Graylog in this specific instance.
As it turns out, Graylog doesn’t have a latest tag on Dockerhub, and Docker will add :latest to any image that you attempt to pull without explicitly adding a tag.
What happens if there’s no :latest tag on the registry? You get the above error. Search your container registry and repo for what tags they use and find the one that makes most sense for you.