The error message you are encountering, "404 Resource not found," typically indicates that the requested resource is not available or cannot be located. Here are a few troubleshooting steps you can try:
Double-check the URL or path you are using to upload the files. Ensure that it is correct and points to the appropriate location or endpoint.
Verify that you have the necessary permissions and access rights to upload files to the specific location. Check the authentication and authorization settings to ensure you have the required privileges.
Ensure that the resource you are trying to access or upload the files to exists. Check if the Form Recognizer service is properly provisioned and configured in your Azure subscription. Also, verify that the service is in the same region as the location you are attempting to access.
If you are using the Azure web UI, try clearing your browser cache and cookies, or use an incognito/private browsing window to rule out any browser-related issues.
Check the documentation and support resources provided by Microsoft for Form Recognizer. They might have specific troubleshooting steps or known issues related to the error you are experiencing.