No sitemap found
What this means
No sitemap was discovered at the conventional location or declared in robots.txt. Discovery then depends entirely on internal linking, which leaves recently added and deeply nested pages waiting to be found.
How to fix it
Publish a sitemap covering every indexable URL and declare it in robots.txt. Most frameworks and CMSs can generate one automatically.
Fix effort
This check needs review: the change can be drafted for you, but a person has to approve the wording or choose the target before it ships.
Authoritative source
https://developers.google.com/search/docs/crawling-indexing/sitemaps/overview
Find every page this affects
CrawlX runs this check — and 161 others — across your whole site, ranks the findings by estimated impact, and opens the fixable ones as pull requests. Free for 500 URLs.