Gets a health check of the DNS settings for the CNAME record configured for a repository's GitHub Pages.

The first request to this endpoint returns a 202 Accepted status and starts an asynchronous background task to get the results for the domain. After the background task completes, subsequent requests to this endpoint return a 200 OK status with the health check results in the response.

To use this endpoint, you must be a repository administrator, maintainer, or have the 'manage GitHub Pages settings' permission. A token with the repo scope or Pages write permission is required. GitHub Apps must have the administrative:write and pages:write permissions.