
Try using a different browser, private browser window or disable your browser extensions. There are some ad blockers that will block the Filestack (3rd party uploader) selection panel.
If none of that will work the Classic workflow uses a different uploader and doesn't do all of the checks so it is the fallback option. It does not work with subscription processing quotas though.
Interesting note: There are a TON of McCutcheon's in our system.