Perhaps your firewall and/or browser are blocking the file upload. In such
cases, I'd usually suggest either trying a different browser, or trying
another network (if you are working behind a firewall).

Given the size of the file, perhaps your browser was trying to do the
upload, and you didn't give it enough time...

If you are using Safari on a MAC, please try Firefox. Safary has a
longstanding bug on file uploads which sometimes prevents the file uploads.