An XML Sitemap is an extremely useful tool in an SEO's arsenal. It allows you to unambiguously declare exactly which URLs you wish to be indexed on a website.

And this is also the only URLs an XML Sitemap should contain - only the URLs you actually want indexed.

As a minimum, these must be URLs that return a 200 status code, and are indexable. As such, the XML Sitemap Hints serve to highlight instances where this is not the case.

Sitemap URLs that do not return 200

There are 5 Hints that relate to URLs which don't return a 200 status:

1. Not Found (4XX) URL in XML Sitemaps
2. Redirect (3XX) URL in XML Sitemaps
3. Error (5XX) URL in XML Sitemaps
4. Forbidden (403) URL in XML Sitemaps
5. Timed out URL in XML Sitemaps

Sitemap URLs that are not indexable

There are 3 Hints that relate to URLs which are not indexable:

1. Canonicalized URL in XML Sitemaps
2. Disallowed URL in XML Sitemaps
3. Noindex URL in XML Sitemaps

URL in multiple XML Sitemaps

This one is an insight rather than an issue (as there's nothing actually wrong with this), but it can be useful to know:

• URL in multiple XML Sitemaps