# X_SITEMAP_ENTRY_INVALID

## Means

a sitemap entry carries a lastmod or a locale the sitemap cannot write

## Typical cause

a prerender() entry (or a page handed to buildSitemap) has a lastmod that is not an ISO 8601 date with an explicit zone, or names a locale the app does not route

## Fix

`x verify --json` after `prerender()` in the route file named in cause answers `lastmod` as a `Date` or an ISO 8601 string with a zone (`row.updatedAt`) and only routed locales in `locales`

[SEO](/error-codes#seo)