kb_rag.py: Getting an error with RetrieveAndGenerate operation

Hello, I created an S3 bucket and a knowledge base on top of it, with pdf documents uploaded into the S3 bucket. I followed the exact code in kb_rag.py; Only difference is I used llama3 model instead of claude-3 sonnet. I'm getting an error "botocore.errorfactory.ValidationException: An error occurred (ValidationException) when calling the RetrieveAndGenerate operation: The model arn provided is not supported. Please check your configuration and retry the request." I've attached the screenshot of the issue for reference. Is there anything I can do to resolve this?