Troubleshooting Workflow for Knowledge Base Message Search

Hi, I'm just trying to create the simplest WF, Message Received->Search knowledge base (Used a simple text file)->Send Message (with a prompt to respond the question with the "Result" from the search). When I test it, it always respond that it does not have that info in the knowledge base, like if it is not finding anything on it. What am I missing? or do you know of an example similar to what I'm doing, so I can compare or follow steps? Thanks.