Error with default-app-name when creating session in ADK agent deployment on AI Engine

[kevinfe]

HI all

We deployed a demo agent to AI Engine using ADK for testing, using VertexAiSessionService for session persistence. Then, after getting the agent instance by calling agent_engines.get("xxxx"), when we call create_session, it reports an error saying 'App name default-app-name is not valid'."
The complete error message as follows：

Error Details: {"detail":"Agent Engine Error: An error occurred during invocation. Exception: App name default-app-name is not valid. It should either be the full ReasoningEngine resource name, or the reasoning engine id.\nRequest Data: {'user_id': 'test_user_123'}"}
How to solve this error？