Thanks for sharing. From reviewing the Site Kit information you kindly shared, I don’t see anything obvious that would be causing this error. Unfortunately I didn’t see any information with regards the other questions asked above, which can be useful to determine any host related issue. Please share the following:
- Do you see any warnings or errors when checking yourSite Health status (Tools > Site Health > Status), which differs from your Site Health information requested above? Such errors may include REST endpoint references.
- Have you been able to set up Site Kit on this site previously, or on any other sites on the same hosting platform?
To help rule out any local, VPN or network issues impacting set up, you may also wish to confirm you can complete Site Kit set up using this disposable WordPress site.
Let me know if you have any questions with the above.