Product:
Cognos BI 10.1.1
Windows 2008 R2 server

Symptom:
After restart of the Cognos BI server you can not get into the Cognos connection or that the Business insight give error :

DPR-ERR-2014 Unable to load balance the request because no nodes in the cluster are available, or no nodes are configured for the service: buxService.

Background:
You have a two server setup,
One server with Cognos Content Manager and Cognos Gateway (named A)
One server with Cognos Application tier ( for BI reporting, named B )

The Cognos Configuration is pointing the primary dispatcher to the Cognos Content Manager server A, but this server does not have all the functionality installed to handle the dispatcher actions.

If you restart server B, then it will point to server A for actions, and server A have the dispatcher service – but not the associated functions needed to perform all actions.

Boot of Cognos servers:
In all Cognos system the server containing the Cognos Content Manager service must be started first. After that the other Cognos BI serves can be started.

Solution:
All servers and gateway must point to the Cognos BI App Servers dispatcher as the only and primary dispatcher for the gateway. This is on server B.

If you want to use the Content Manager server A as primary dispatcher, you must install the Cognos Application tier there.
Then you need to set Report service and Batch Report service to false in Cognos Configuration on Server A, to prevent the heavy reports to be processed on that server.