On the Shared Services Provider –> Search Settings page the Propagation status shows "Query server is not responding"
To resolve the issue please execute following step one at a time and keep reviewing Propagation Status under Search Settings within Shared Services provider
Killing MSsearch.exe and re-spawning it again. (On Index & both the WFE’s)
Open Command prompt and then execute following
Net Stop OSearch && Net Start OSearch
Re- Provision Osearch Service (On Index & both the WFE’s)
stsadm -o provisionservice -action start -servicename OSearch -servicetype "Microsoft.Office.Server.Search.Administration.SearchService, Microsoft.Office.Server.Search, Version=188.8.131.52, Culture=neutral, PublicKeyToken=71e9bce111e9429c"
Setting permission again on propagation location (On all WFE)
stsadm -o osearch -propagationlocation "C:\Program Files\Microsoft Office Servers\12.0\Data\Office Server\Applications"
Clear Configuration Cache (All Server)
Try to a new content source and move the url we wish to be crawled from the (Local Office SharePoint Sites) and then try to start a Full crawl.