Alert configurations needed for ds

[ppcreditplus]

Hi Could anyone help on the configurations needed at yaml end for enaling the alert? Am stuck with the error - Alert test sending failed, [null]. Caused by: org.apache.dolphinscheduler.extract.base.exception.RemotingException: connect to : Host(ip=dolphinscheduler-alert-668df89b7d-9vx8v, port=50052) fail
at org.apache.dolphinscheduler.extract.base.NettyRemotingClient.sendSync(NettyRemotingClient.java:194)
at org.apache.dolphinscheduler.extract.base.client.SyncClientMethodInvoker.invoke(SyncClientMethodInvoker.java:46)
at org.apache.dolphinscheduler.extract.base.client.ClientInvocationHandler.invoke(ClientInvocationHandler.java:55)
... 80 common frames omitted

Could anyone assist on this?