[druid-user] Ingestions are failing in Druid 0.21.1 version.

Hi,

I created Druid cluster with 0.21.1 version and mimicking my production ingestion with linear scaling of middle manager nodes with below error.
After resolving the ip addresses, we understood that communication between middle manager& other nodes running its peon tasks and query&historical nodes are not failing.

Caused by: org.jboss.netty.channel.ChannelException: Failed to connect to host[https://ip-10-134-38-171.us-east-1.aws.athenahealth.com:8291] at org.apache.druid.java.util.http.client.pool.ChannelResourceFactory$2.operationComplete(ChannelResourceFactory.java:167) ~[druid-core-0.21.1.jar:0.21.1] at org.jboss.netty.channel.DefaultChannelFuture.notifyListener(DefaultChannelFuture.java:409) ~[netty-3.10.6.Final.jar:?] at org.jboss.netty.channel.DefaultChannelFuture.notifyListeners(DefaultChannelFuture.java:400) ~[netty-3.10.6.Final.jar:?] at org.jboss.netty.channel.DefaultChannelFuture.setFailure(DefaultChannelFuture.java:362) ~[netty-3.10.6.Final.jar:?] at org.jboss.netty.channel.socket.nio.NioClientBoss.processSelectedKeys(NioClientBoss.java:109) ~[netty-3.10.6.Final.jar:?] at org.jboss.netty.channel.socket.nio.NioClientBoss.process(NioClientBoss.java:79) ~[netty-3.10.6.Final.jar:?] at org.jboss.netty.channel.socket.nio.AbstractNioSelector.run(AbstractNioSelector.java:337) ~[netty-3.10.6.Final.jar:?] at org.jboss.netty.channel.socket.nio.NioClientBoss.run(NioClientBoss.java:42) ~[netty-3.10.6.Final.jar:?] at org.jboss.netty.util.ThreadRenamingRunnable.run(ThreadRenamingRunnable.java:108) ~[netty-3.10.6.Final.jar:?] at

Regards,
Jay

Where is this error showing up? Are all the processes up, running and healthy, including zookeeper?