Error in system log

I am receiving this error message very frequently and it is making the database increase in size very quickly.

JobExecutionFailure: jobId:3232921; ErrorMessage: java.util.concurrent.ExecutionException: com.adventnet.servicedesk.ServiceDeskException: Mail sending failed.; JobInfoObject: {"jobId":[3232921],"moduleName":["MAIL_NOTIFICATION_JOB"],"executorClass":["com.manageengine.servicedesk.jobexecutors.MailNotificationJobExecutor"],"jobInput":["{\\\"ENTITY_NAME\\\":\\\"WORKORDER\\\",\\\"ENTITY_ID\\\":43355,\\\"NOTIFY_TYPE\\\":\\\"UnpickedQueueReqTechNotify_E-Mail\\\",\\\"NOTIFY_FROM\\\":\\\"QUEUEUTIL\\\"}"],"jobInputObjectStore":["com.manageengine.jobscheduler.JobInputObjectStore@1b4576e8"],"errorInfo":[null]}

build 9228 with mssql