Can't bind Kamelet to Knative broker

apiVersion: camel.apache.org/v1alpha1
kind: KameletBinding
metadata:
  name: telegram-binding
spec:
  sink:
    ref:
      apiVersion: eventing.knative.dev/v1
      kind: Broker
      name: default
  source:
    properties:
      authorizationToken: 'xxx'
    ref:
      apiVersion: camel.apache.org/v1alpha1
      kind: Kamelet
      name: telegram-source 

"msg":"Reconciler error","controller":"integration-controller","name":"broker","namespace":"jbouska","error":"error during trait customization: sinkbinding can only be used with a single sink: found 0 sinks","errorVerbose":"sinkbinding can only be used with a single sink: found 0 sinks\nerror during trait customization\ngithub.com/apache/camel-k/pkg/trait.Apply\n\tgithub.com/apache/camel-k/pkg/trait/trait.go:47\ngithub.com/apache/camel-k/pkg/controller/integration.(*deployAction).Handle\n\tgithub.com/apache/camel-k/pkg/controller/integration/deploy.go:56\ngithub.com/apache/camel-k/pkg/controller/integration.(*ReconcileIntegration).Reconcile\n\tgithub.com/apache/camel-k/pkg/controller/integration/integration_controller.go:273\ngithub.com/apache/camel-k/vendor/sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).reconcileHandler\n\tgithub.com/apache/camel-k/vendor/sigs.k8s.io/controller-runtime/pkg/internal/controller/controller.go:244\ngithub.com/apache/camel-k/vendor/sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).processNextWorkItem\n\tgithub.com/apache/camel-k/vendor/sigs.k8s.io/controller-runtime/pkg/internal/controller/controller.go:218\ngithub.com/apache/camel-k/vendor/sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).wor