Suddenly this morning I started getting error
Descendant and Ancestor axes are disabled. Set FastQueryDescendantsDisabled setting to false to enable these axes.
When researched found there is a setting in web.config
<!-- FAST QUERY DESCENDANTS DISABLED Determines whether ability to select items through Ancestors/Descendants axes should be disabled in fast query. Default value: false --> <setting name="FastQueryDescendantsDisabled" value="false" />
Surprised that this setting has not been changed ; to invetigate further i searched FastQueryDescendantsDisabled invetigate whole root solution folder..
Then I found one more place where it was true..changed and life back to normal,
As per sitecore fast query cheat sheet whenever we change this we should clean up the databases.
Note If the FastQueryDescendantsDisabled setting, in the web.config file, is set to true and then changed back to false, you must rebuild the Descendents table. To rebuild the Descendents table, click Sitecore, Control Panel, Databases, Clean Up Database and run the Clean Up Database wizard.