ConversationEntry resource not working

Hi guys,

Based on the YML for inbound there is a conversation entry resource which it seems to be the only way to import messages sent both by a Salesforce User and an End User.

We've been trying to test this but we keep getting 400 error

<img width="721" height="724" alt="Image" src="https://github.com/user-attachments/assets/d9f0b731-bf21-4ca5-b7d9-89e02a8c0fc7" />

Any idea?