technical issue with connecting to the Site Kit authentication service

Thanks for reaching out @jevil . This message can occur if there is something blocking access to the Site Kit service. This could be at host or browser level. So we can determine more on this, please share the following:

1. Your Site Health information. You can use this form to share privately if preferred. 
2. When checking the Site Kit dashboard from a Chrome browser incognito window does the same occur? This can help indicate a browser related block.
3. Do you see this message when attempting to set up Site Kit from this disposable WordPress site?

Let me know if you have any questions with the above.