unfortunately that error message is not much saying, but a common mistake. We've changed the way you need to copy over injected UI vars in your plugin. Add to your plugin description (i.e. inside the object you pass to
server.injectUiAppVars('youAppId', async () => (
yourAppId must match the
id you gave your application in the
app part of that file. ALso if your plugin was running earlier already, you might have the old
injectVars key in your app definition, which you can remove.
kibana_sample_plugin for an example of how to migrate the