Why can't I add a namespace in Container Registry?

Setting up a namespace fails in IBM Cloud® Container Registry.

When you run ibmcloud cr namespace-add, you are unable to set your entered value as the namespace.

The following alternatives are possible causes:

• Scenario A. You used invalid characters in the namespace value.
• Scenario B. You entered a namespace value that is already being used by another IBM Cloud organization.
• Scenario C. A namespace was recently deleted and you're reusing its name. If the namespace that was deleted contained many resources, the deletion might not yet be fully processed by Container Registry.

You can fix this problem in the following ways:

Follow any instructions that are in the returned error message. If that is not successful, or no instructions are provided, try the following options:

• Scenario A. Check that you entered a valid namespace:
  • Your namespace must be unique across all IBM Cloud accounts in the same region.
  • Your namespace must be 4 - 30 characters long.
  • Your namespace must start and end with a letter or number.
  • Your namespace must contain lowercase letters, numbers, hyphens (-), and underscores (_) only.
• Scenario B. Choose a different value for your namespace.
• Scenario C. If you're re-creating a namespace that was deleted, and it contained many images, try again later.