I suggest trying these troubleshooting steps:

• Try Incognito/Private Mode: This is the quickest way to eliminate browser extensions or "gunked-up" cache from interfering with the upload script.
• Switch Browsers: If you're on Safari or Edge, try Google Chrome; it generally has the highest compatibility with Intuit’s uploaders.
• Clear Cache & Cookies: If you prefer your current browser, clear the cache and then restart your computer to refresh the session.

Make sure you are using an accepted file format when uploading: PDF, JPG, PNG, and CSV.

Hope this helps!