Common Module reuse — how to call a shared flow from multiple inbound call flows

Having some config trouble here. I need to reuse a Common Module across multiple inbound call flows. I am using Architect Data Actions. The flowId seems correct, but the call fails with 404 Not Found. Here is my JSON payload:

{
 "actionType": "Flow",
 "flowId": "shared-module-id-123"
}

I verified the module exists via GET /api/v2/architect/flows. Is there a scope issue or a specific permission required for cross-flow invocation?