Custom Sender Email in 18.4

Hi All,

Currently we are wotking on 18.4 version and we are trying to use the custom Email Sender Option,

I tried confirguring my Sender Display Name and Sender Email when i tried executing it i am getting the following error,

Sender Email did not resolve to a valid email address and the logs,

Could someone help me in this pls.

2019-01-25 12:34:24,110 [Appian Work Item - 5307 - execution01 : UnattendedJavaActivityRequest] ERROR com.appiancorp.util.BundleUtils - Cannot retrieve the value for key "address.customSenderOption_appian_internal.displayName" from the bundle.
2019-01-25 12:34:24,113 [Appian Work Item - 5307 - execution01 : UnattendedJavaActivityRequest] ERROR com.appiancorp.process.engine.UnattendedJavaActivityRequest - An error occurred while executing activity: id=268637329, classname=com.appiancorp.process.runtime.activities.SendEmailActivity
java.lang.RuntimeException: Sender Email did not resolve to a valid email address
	at com.appiancorp.process.runtime.activities.SendEmailActivity.validateSenderEmail(SendEmailActivity.java:440)
	at com.appiancorp.process.runtime.activities.SendEmailActivity.execute(SendEmailActivity.java:264)
	at com.appiancorp.suiteapi.process.framework.AbstractActivity.perform(AbstractActivity.java:104)
	at com.appiancorp.process.runtime.framework.LegacyActivityExecutor$2.call(LegacyActivityExecutor.java:90)
	at com.appiancorp.process.runtime.framework.LegacyActivityExecutor$2.call(LegacyActivityExecutor.java:87)
	at com.appiancorp.common.ContextClassLoaderSwitcher.runInContext(ContextClassLoaderSwitcher.java:21)
	at com.appiancorp.process.runtime.framework.LegacyActivityExecutor.execute(LegacyActivityExecutor.java:87)
	at com.appiancorp.process.engine.UnattendedJavaActivityRequest.execute(UnattendedJavaActivityRequest.java:83)
	at com.appiancorp.process.engine.UnattendedJavaActivityRequest.execute0(UnattendedJavaActivityRequest.java:55)
	at com.appiancorp.process.engine.ContinuationRequest.executeOuter(ContinuationRequest.java:71)
	at com.appiancorp.process.engine.ContinuationRequest.execute(ContinuationRequest.java:100)
	at com.appiancorp.process.workpoller.UnattendedRequestHandlerBean.onMessage(UnattendedRequestHandlerBean.java:35)
	at com.appiancorp.process.workpoller.WorkItem.run(WorkItem.java:84)
	at org.springframework.jca.work.SimpleTaskWorkManager$DelegatingWorkAdapter.run(SimpleTaskWorkManager.java:239)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)
2019-01-25 12:34:24,725 [Appian Work Item - 5308 - execution01 : SendNotificationRequest] WARN  com.appiancorp.ap2.service.PortalNotificationServiceJavaImpl - A notification broadcast has been prevented because the number of recipients [214] would exceed the configured limit of [100]. Adjust conf.notifications.MAX_RECIPIENTS to a value greater than [100] as necessary for future notifications.