I’m attempting to create an automation in Prefect 3 that sends Slack notifications whenever a flow enters a state. This works perfectly when I run it locally, but fails on our Prefect server running on a Kubernetes cluster.
The error message I receive is:
"The notification block was invalid: KeyError(\"No class found for dispatch key 'slack-incoming-webhook' in registry for type 'Block'.\")",
Both setups are running Prefect version 3.0.0. I created the blocks and automations using exactly the same configurations. Sending Slack notifications from a task on the cluster works, so it is possible to send notifications to Slack from the cluster.
Could anyone help to clarify why this issue occurs and how to resolve it?