Sitemap Index Issue

Hi, Google could not index my sitemap: https://sinoindustry.com/sitemap_index.xml The cause pointed out by Google Search Console is ‘noindex’ detected in ‘X-Robots-Tag’ http header. I’ve checked my wordpress and rankmath settings which are all right.

I have also contacted my server. Here are their tests and suggestions:

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From Server Siteground Technical Support:

I have checked on the headers of the site, and currently, it appears that the X-Robots-Tag is not within:

HTTP/2 200
server: nginx
date: Fri, 21 Jun 2024 07:37:22 GMT
content-type: text/html; charset=UTF-8
vary: Accept-Encoding
link: <https://sinoindustry.com/wp-json/&gt;; rel=”https://api.w.org/&#8221;
link: <https://sinoindustry.com/wp-json/wp/v2/pages/6&gt;; rel=”alternate”; type=”application/json”
link: <https://sinoindustry.com/&gt;; rel=shortlink
x-httpd-modphp: 1
host-header: 8441280b0c35cbc1147f8ba998a563a7
x-proxy-cache-info: DT:1
x-cdn-c: static

The X-Robots-Tag is an HTTP header used to control how search engines index and serve a webpage. It provides similar functionality to the robots meta tag but can be applied to non-HTML files such as PDFs, images, and other resources.

I have also reviewed the .htaccess file of the application and found that this implementation is absent.

The provided URL and the sitemap_index.xml are generated from the third-party SEO plugin used, so I recommend providing them with the headers log from the above, so they can investigate further: