Vertex Agent Builder: Failed to generate response

[arsentiev_alex]

Hello, I'm using Vertex Agent Builder with an OpenAPI tool that calls Cloud Function. The chatbot works well and generates a response. However, after calling the tool, it does not allow to ask any follow up questions. When I'm trying to type anything there is an error message "Failed to generate response". 

There is nothing in debug trace so not really sure how to fix it. I'm guessing maybe the tool connection was not closed properly which doesn't allow for new interactions?

Any help is much appreciated