Hi Rene,
Thanks for reaching out to us. I see that your issue is with setting up the client library with the link you’re inputting giving you a 404 error code. Could you please try opening a new incognito window in your Chrome browser and try again? If this doesn’t work, since this is a client library concern, could I ask you to put your concern here, in the issues portion of the client library’s Github page? Our client library support team would be more than happy to assist you with your issue. Let me know if you have further questions about the API.
Thank you,
Bryan, Google Ads API Team