Google is returning error 400 and redirect_uri_mismatch
This means you have put the wrong URL into the “Authorized redirect URI” in Google Credentials.
The URL shown in the error is used to make the forward call to your website. EDD Google Drive is sending this URL to Google after which Google will redirect back to your website.
So the URL which is shown under Request Details should be the one which should be put in the Google in these two should be exactly the same.