SharePoint 2010: Internal Server Error exception while performing Search

Issue: While performing search on any level of the site users getting the error message:

Error Message: Internal server error exception: Troubleshoot issues with Microsoft SharePoint Foundation

Background: Our SharePoint 2010 Search is just recently been extended to next level and when user performed search they started getting error message. There were no major changes in the search service application.

But looking at the event logs it seems to be an issue with the Configuration of the search topology.

Event ID 8031 was reported with the message.  

An exception occurred while updating addresses for connected app {eaf6c00c-cc3f-460e-8bf2-ad9b991ea6ea_aa16845d-045a-46bc-bbc6-d701ff13950d}. The uri endpoint information may be stale. System.InvalidOperationException: The requested application could not be found at Microsoft.SharePoint.SPTopologyWebServiceApplicationProxy.ProcessCommonExceptions(Uri endpointAddress, String operationName, Exception ex, SPServiceLoadBalancerContext context) at Microsoft.SharePoint.SPTopologyWebServiceApplicationProxy.ExecuteOnChannel(String operationName, CodeBlock codeBlock) at Microsoft.SharePoint.SPTopologyWebServiceApplicationProxy.GetEndPoints(Guid serviceId) at Microsoft.SharePoint.SPConnectedServiceApplicationAddressesRefreshJob.Execute(Guid targetInstanceId) bf94139a-66f8-4aab-af31-406a5ebb6db9

Troubleshooting:

Checked the search settings on all the levels and it was fine.

Checked the configuration changes from the search service application prospective.

Checked the permissions level of the search Content access account and Search Service account.

Everything was fine until we realized.

Resolution:

That the web application which was associated with the Search Service Proxy but the Search Service Proxy was not associated with the Search Service application. We re-associated the correct web application with a valid Search service application proxy and asked user to perform the search and it did worked fine.

You need to go to CA, Manage service applications option. To do this, follow these steps:

1.    Open Central Administration.

2.    Click Manage web applications.

3.    Select the affected web application.

4.    On the ribbon, click Service Connections.

5.    Under Configure Service Application Associations, select the valid Search service application proxy check box.

Another reference with different resolution: http://blogs.technet.com/b/sushrao/archive/2011/12/02/sharepoint-2010-search-internal-server-error-exception-system-nullreferenceexception.aspx

Product Applies to: SharePoint Server 2010.