@Katrina
Hello! I'm here to help you with your issue. It sounds like there might be a problem with accessing the files you've uploaded for your assistant's knowledge base. To assist you better, could you please confirm if you have the file IDs of the PDFs that you're trying to use? If you have them, please provide the file IDs so we can proceed with troubleshooting the issue. If you don't have the file IDs handy, we may need to look into your account details further. Please let me know how you'd like to proceed!