Exchange 2013: Internal error while processing request

The FastFeeder component received a connection exception from FAST. Error details: System.ServiceModel.FaultException`1[System.ServiceModel.ExceptionDetail]: Internal error while processing request (Fault Detail is equal to An ExceptionDetail, likely created by IncludeExceptionDetailInFaults=true, whose value is: Microsoft.Ceres.InteractionEngine.Component.ProcessingEngineException: Internal error while processing request

Event ID: 1006

This is due to the ExchangeFastSearch attempting to look for a security group called "ContentSubmitters" - although is not created automacially by Exchange 2013 and can be created manually - simply create a security group in the "Exchange Security Groups" OU called "ContentSubmitters" and assign the "Administrators" and "NetworkService" Full Access. And then restart the following services:

Microsoft Exchange Search
Microsoft Exchange Search Host Controller