Architect Data Action 404 when calling shared Common Module flow via REST

Architect & Flows
1

Trying to centralize some auth logic by pulling it into a common module and calling it from various inbound flows. I’ve got the module published and deployed, but the Data Action keeps bombing out with a 404.

The endpoint looks right based on the docs. I’m using a Get REST Proxy action with this config:

Method: POST
URL: https://{{instance}}.my.nice.incontact.com:443/nicecxone/api/v2/interactions/actions/sharedFlowCall
Auth: OAuth2

Payload is minimal:

{
 "flowId": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
 "input": {
 "agentId": "{{contact.agentId}}"
 }
}

The flow ID is definitely correct. I can see the shared module in the UI. I’ve checked the OAuth token scope and it has flow:view and interaction:write. The error response body just says "error": "not_found", "message": "Resource not found".

Is there a specific header I’m missing? Or does the shared module need a different endpoint structure than standard flows? The documentation is pretty thin on the actual HTTP call details for cross-flow invocation.