We have multiple sites in a Umbraco directory.
Sites are mainly cloned in English or French.
That sites search is managed by the Examine engine. The indexes are located respectively in IndexEN and IndexFR folders.
After analyzing the indexes in the IndexFR folders I observed that mainly all sites are indexed, but there are some sites that are not (respectively, the search result is always empty).
Why? What could be the main causes that a Umbraco node (that corresponds to a site) is not indexed by the Examine engine?