BlockManager Fetch Exceptions

org.apache.spark.storage.BlockFetchException: Failed to fetch block from 1 locations. Most recent failure cause:
    at org.apache.spark.storage.BlockManager$$anonfun$doGetRemote$2.apply(BlockManager.scala:595)
        at org.apache.spark.storage.BlockManager$$anonfun$doGetRemote$2.apply(BlockManager.scala:585)
        at scala.collection.mutable.ResizableArray$class.foreach(ResizableArray.scala:59)
        at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:48)
        at org.apache.spark.storage.BlockManager.doGetRemote(BlockManager.scala:585)
        at org.apache.spark.storage.BlockManager.getRemote(BlockManager.scala:570)
        at org.apache.spark.storage.BlockManager.get(BlockManager.scala:630)
        at org.apache.spark.CacheManager.getOrCompute(CacheManager.scala:44)
        at org.apache.spark.rdd.RDD.iterator(RDD.scala:268)
        at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:73)
        at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:41)
        at org.apache.spark.scheduler.Task.run(Task.scala:89)
        at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:214)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at java.lang.Thread.run(Thread.java:745)
    Caused by: java.io.IOException: Failed to connect to ip-10-12-46-235.us-west-2.compute.internal/10.12.46.235:55681
        at org.apache.spark.network.client.TransportClientFactory.createClient(TransportClientFactory.java:216)
        at org.apache.spark.network.client.TransportClientFactory.createClient(TransportClientFactory.java:167)
        at org.apache.spark.network.netty.NettyBlockTransferService$$anon$1.createAndStart(NettyBlockTransferService.scala:90)
        at org.apache.spark.network.shuffle.RetryingBlockFetcher.fetchAllOutstanding(RetryingBlockFetcher.java:140)
        at org.apache.spark.network.shuffle.RetryingBlockFetcher.access$200(RetryingBlockFetcher.java:43)
        at org.apache.spark.network.shuffle.RetryingBlockFetcher$1.run(RetryingBlockFetcher.java:170)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        ... 3 more
        Caused by: java.net.ConnectException: Connection refused: ip-10-12-46-235.us-west-2.compute.internal/10.12.46.235:55681
            at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
        at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:717)
        at io.netty.channel.socket.nio.NioSocketChannel.doFinishConnect(NioSocketChannel.java:224)
        at io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe.finishConnect(AbstractNioChannel.java:289)
        at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:528)
        at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:468)
        at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:382)
        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:354)
        at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:111)
        ... 1 more