New Foundry Agent Issue

Because Preview works, the model and instructions are probably fine. The published bot uses the agent’s stable endpoint and a different authorization path, so I would check versioning and identity first.

1. Confirm the active/published version is the same version that has File Search enabled and the vector store/files attached. A working draft in Preview does not prove the endpoint is serving that version.

2. Test a question that does not require the uploaded documents. If that works, inspect the published agent identity and grant it the required data-plane roles on every backing resource the tool uses, such as Search or Storage.

3. “Individual/Just you” publishing uses RBAC. Confirm your user has an appropriate Foundry role on the project, then sign out and back in after role changes.

4. Start a fresh Copilot chat. In Teams, send /foundry_new_preview to reset a conversation stuck after a tool error.

Finally, check the agent trace/diagnostics for the failed timestamp; the generic Copilot message hides the real authorization or tool exception.