This is a cache of https://fess.codelibs.org/12.3/admin/failureurl-guide.html. It is a snapshot of the page at 2018-10-09T00:01:42.767+0000.
Failure url page display urls/paths which are not correctly crawled.
Display Failure url
Select System Info > Failure url in the left menu to display a list page of failure urls, as below.