Resolution Steps :

-> I verified the report logs and below was the error logged :

extensionfactory!ReportServer_0-4!20f8!07/30/2015-13:15:03:: e ERROR: Exception caught instantiating Report Server Email report server extension: Microsoft.ReportingServices.Diagnostics.Utilities.ServerConfigurationErrorException: The report server has encountered a configuration error. .

library!ReportServer_0-4!20f8!07/30/2015-13:15:03:: e ERROR: Throwing Microsoft.ReportingServices.Diagnostics.Utilities.ServerConfigurationErrorException: Email Provider has no server or pickup directory specified, Microsoft.ReportingServices.Diagnostics.Utilities.ServerConfigurationErrorException: The report server has encountered a configuration error. ;

->I have updated the <SMTPServerPickupDirectory> parameter in the rsreportserver config file and it worked.