Configure Search on Sites Using Forms Authentication

The default SharePoint search crawler cannot crawl on sites that are set up to use Forms Authentication or sites that use a security certificate. 
Alternate Access Mappings provide an alternate URL to access the same SharePoint site and
can also be set to different zones such as Default, Intranet, Internet or Extranet.  Create an AAM to a site that cannot be crawled and assign it to the default zone. 
Set the authentication method for this mapped site to Windows  Authentication. 
This is configured via the ‘Create or extend Web application’ menu from Central Administration -> Application Management. 
The original site that cannot be currently crawled should be moved over to a zone other than the default zone.  The newly created AAM site can then be set to use Windows Authentication, should not use a Security Certificate and should be assigned to the default zone.