cRUL 28 Error

I am getting this error during the Site Health test

REST API Endpoint: https://www.riverhillartist.com/wp-json/wp/v2/types/post?context=edit
REST API Response: (http_request_failed) cURL error 28: Operation timed out after 10000 milliseconds with 0 bytes received

It is impossible to edit the site with this problem. How can I fix this?

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