You submitted your sitemap in Google Search Console, and instead of a green "Success" you see an error. These are the ones we get asked about most.
- Couldn't fetch. Google could not download the sitemap. Open its address in your browser: is the file really there? Is it blocked in your robots.txt, or only visible when you are logged in? Sometimes the server was just busy, and the next attempt works.
- Sitemap is HTML. Google got a web page instead of XML. Usually the sitemap is missing and your site shows its "page not found" page, without a 404 status. Upload the sitemap again and check the address.
- URL not allowed. The sitemap lists pages that are not in its own place. A sitemap at https://www.example.com/sitemap.xml may only list pages that start with https://www.example.com/, so not http://, not example.com without www, and not a page above the sitemap's folder.
- Invalid date. A <lastmod> tag has a date in the wrong format. Use dates like 2021-09-21 or 2021-09-21T10:00:00+00:00.
- Compression error. A sitemap.xml.gz file that is not a valid gzip file. Upload it again, in binary mode if you use FTP.
After a fix, open the sitemap in Search Console and submit it again, so Google does not wait for its next visit.