Thanks for reaching out here. We’re sorry to hear that you’re having trouble with the XML sitemap.
When looking at the sitemap index https://ilbirdk.ga/sitemap_index.xml, it took a bit longer for us. However, after the first load, the sitemap index almost instantly.
In addition, we see the sitemap index is redirecting to the https://ilbirdk.ga/sitemap_index.xml?i=1 (adding an additional query string ?i=1) in the URL.
When running a cURL test to both of the relevant URLs, we see the following output with 403 forbidden HTTP status code:
curl -I https://ilbirdk.ga/sitemap_index.xml
HTTP/2 403
server: nginx
date: Thu, 22 Jul 2021 06:28:04 GMT
content-type: text/html
content-length: 146
vary: Accept-Encoding
So, that explains why the sitemap always fails for you. Something on your site is modifying the sitemap index’s HTTP status code from 200 to 403 and as such, the crawler is having trouble crawling the sitemap index.
So, we recommend you please perform a full conflict check and run the relevant cURL test until you see the 200 HTTP status code to find the exact cause of the issue.
The fastest way to rule out any conflict, is to deactivate all non-Yoast plugins and switch to a standard theme like Twenty Twenty.
Please test this on your development or staging site, if you have one. If not, we recommend using the Health Check & Troubleshooting plugin. This plugin has a troubleshooting mode, which does not affect normal visitors to your site.
If you’re unfamiliar with checking for conflicts, we’d like to point you to a step-by-step guide that will walk you through the process: How to check for plugin conflicts
If you do not feel comfortable doing this yourself or if this does not solve your issue, our Yoast SEO Premium plugin comes with one year of (technical) support.
