Multi-account Containers, existing containers disappeared, no way to create new ones

[Nightwatch]

The option to ADD or manage NEW CONTAINER is missing from the container pop-up. “Personal Work Banking Shopping Facebook” defaults only remain. All of my customized container names suddenly disappeared. I Deleted and re-installed the Container extension, but the options to add new containers are still missing.

[juraj.masiar]

When you hold the “+” button (the one that creates new tab), it should show this:

And clicking “Manage containers” opens this page:
about:preferences#containers

And there you should see “Add container” button.