Find the below log file for this error.It will accours when you did a mistake in Config file.
$FASTSEARCH/var/log/configserver.scrap
It's one of the FATAL error.The main causes for this error is,some program/Application using the port what ESP use.
Error :
Failed to start ConfigServer:
error: (226, 'Address already in use')
Solution :
Start the configserver on another port or shut down the program using the one you are trying to use.(Edit the Port element in config file)