I often get “The search request was unable to connect to the Search Service.” on my development/server environment.
Though Office SharePoint Server Search and Windows SharePoint Services Search windows services are running fine.
1.Restart “Office SharePoint Server Search” and “Windows SharePoint Services Search” Windows Services
2.do IISRESET (Or go for App-Pool Recycle)
This problem can also occur in new environments where these services are not configured properly
1.Go to Operations tab in Central Administration
2.Select “Services on Server” from Topology and Services
3.Select your Indexing/application Server from the server menu and make sure “Office SharePoint Server Search” and “Windows SharePoint Services Search” services are started.
Hope it helps.