For some reason, your domain URL is not matching the browser service key URL list.
This is common when we’re not using an actual domain, but dynamic IPs and such.
In this case, I recomend not using a defined address, but yet, enabling any addresses, by removing the referers.
After doing so, this should appear in google console for the browser key:
Referers: Any referer allowed
Please allow a couple of minutes for the setting to be propagated. Then save your options and try the downloader again.
As an additional note, please make sure that in Google Console “Services” options, you have enabled both Drive API and Drive SDK.