Sitemap validator error – Incorrect http header

Hi @andrect,

Thank you for reaching out.

If your sitemaps are served as HTML, then most often this is caused by a caching plugin that is caching them. Please exclude your sitemaps from being cached – see https://yoast.com/help/exclude-sitemaps-from-cache/

Cache disable, error persist
??

Hey,

If after disabling/clearing the cache the issue persists, I’d recommend doing a conflict check to see with what combination of plugins/themes the sitemaps are switched from XML output to HTML. You can read more about doing a conflict check here: https://yoast.com/help/how-to-check-for-plugin-conflicts/

Even the sitemap.xml not showing up has a problem for google?
the sitemap_index.xml works fine

Hey,

I’m not completely sure what you mean. Let me clarify. When the Yoast SEO sitemaps are activated, we redirect the WordPress sitemap under /sitemap.xml to /sitemap_index.xml.

If the sitemap_index.xml works correctly, all is good and you can submit this to Google Search Console. See: https://yoast.com/help/submit-sitemap-search-engines/

ok
thx

None of the proposals you indicated did not work.