Thanks for sharing. From inspecting your setup all seems fine. To ensure it’s not a user permissions issue have you checked the Google account which this user used to setup Site Kit, while ensuring this Google account has access to that Analytics property at analytics.google.com?
You can also perform the following check to ensure this is specific to this user or Google account:
- Access that Analytics from from analytics.google.com
- Provide access to that Analytic property to another Google account
- Create another test WordPress administrator user on this site
- Login to the site with this new administrator user and then connect Site Kit using that Google account
If you confirm the user does have access to this Analytics property based on the Google account they used to setup Site Kit please share the full error message they encounter and we can investigate this further.