Hello,
This plugin project has been archived (⚠️ This plugin is deprecated ⚠️ · Issue #57 · joplin/plugin-kanban · GitHub), and it is suggested to migrate to YesYouKan. However, the design philosophy between this plugin and YesYouKan is quite different. If you have difficulty migrating, you may consider my fork. It comes with new features and bug fixes. More information is available at KanMug - A Forked Project of the Original Kanban Plugin.