Kee plugin for Firefox suddenly stopped working

[Jon99999]

Solution is here:

You are not logged in to your password manager. Open Kee Vault or KeePass to enable Kee

I had this or a similar problem with Kee/KeePass2 on Firefox on ONE of three Win10 computers. It was driving me insane. Usual troubleshooting did not solve the problem. Uninstalled everything, reinstalled, etc, no joy. The solution that finally worked for me was to go into my KeePass DB, select the top level folder, right-click it, and choose “Set as Kee home group”.