Why would Linux Docker fail downloading files from private gcr.io?

### Issue So... I have tested many different commands and it all works great except docker pull gcr.io/... which always says I don't have enough permissions: > _ERROR: unauthorized: You don't have the needed permissions to perform this operation, and you may have invalid credentials. To authenticate your request, follow the steps in: https://cloud.google.com/container-registry/docs/advanced-authentication_ Why would that be? I'm 100% sure I'm properly logged into Google Cloud since I can run commands such as kubectl ... that require that very same authorization. ### My Environment #### Host I am running Linux Ubuntu (at this time 22.04) on amd64. #### Guest On that box, I need to run a VM for various reasons. So I have another Ubuntu 22.04 install which runs in a VirtualBox VM. Everything, as mentioned above, works just fine. #### Docker At this time, docker is installed as a snap, version 20. _**Note:** I could not use the default apt-get packages because these are not being updated and thus it is very old._ The failing command is something like: docker pull gcr.io///:main-123456