VBS - trying to create a workspace but getting an error that there aren't any available environments

We have been using Oracle Visual Builder Studio for a while now, to make Redwood config changes. But yesterday/today when we're trying to create new workspaces, we're getting a message which is preventing us from creating a workspace:

Previously we've been able to select an environment from that list and create workspaces without issue.

I've checked the Environments page and they're all looking good:

I've tried manually adding the name in there, and then get an error message which prevents the creation:

I've tried deleting some workspaces in case it was a limit issue, but that hasn't helped either.