diff --git a/src/main/java/com/alipay/remoting/DefaultConnectionManager.java b/src/main/java/com/alipay/remoting/DefaultConnectionManager.java
index 08d501e6..978bbc59 100644
--- a/src/main/java/com/alipay/remoting/DefaultConnectionManager.java
+++ b/src/main/java/com/alipay/remoting/DefaultConnectionManager.java
@@ -25,6 +25,7 @@
 import java.util.concurrent.ArrayBlockingQueue;
 import java.util.concurrent.Callable;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.FutureTask;
 import java.util.concurrent.RejectedExecutionException;
@@ -51,48 +52,48 @@
 public class DefaultConnectionManager extends AbstractLifeCycle implements ConnectionManager,
                                                                Scannable, LifeCycle {
 
-    private static final Logger                                                     logger = BoltLoggerFactory
-                                                                                               .getLogger("CommonDefault");
+    private static final Logger                                                 logger = BoltLoggerFactory
+                                                                                           .getLogger("CommonDefault");
 
     /**
      * executor to create connections in async way
      */
-    private ThreadPoolExecutor                                                      asyncCreateConnectionExecutor;
+    private ThreadPoolExecutor                                                  asyncCreateConnectionExecutor;
 
     /**
      * connection pool initialize tasks
      */
-    protected ConcurrentHashMap<String, RunStateRecordedFutureTask<ConnectionPool>> connTasks;
+    protected ConcurrentMap<String, RunStateRecordedFutureTask<ConnectionPool>> connTasks;
 
     /**
      * heal connection tasks
      */
-    protected ConcurrentHashMap<String, FutureTask<Integer>>                        healTasks;
+    protected ConcurrentMap<String, FutureTask<Integer>>                        healTasks;
 
     /**
      * connection pool select strategy
      */
-    protected ConnectionSelectStrategy                                              connectionSelectStrategy;
+    protected ConnectionSelectStrategy                                          connectionSelectStrategy;
 
     /**
      * address parser
      */
-    protected RemotingAddressParser                                                 addressParser;
+    protected RemotingAddressParser                                             addressParser;
 
     /**
      * connection factory
      */
-    protected ConnectionFactory                                                     connectionFactory;
+    protected ConnectionFactory                                                 connectionFactory;
 
     /**
      * connection event handler
      */
-    protected ConnectionEventHandler                                                connectionEventHandler;
+    protected ConnectionEventHandler                                            connectionEventHandler;
 
     /**
      * connection event listener
      */
-    protected ConnectionEventListener                                               connectionEventListener;
+    protected ConnectionEventListener                                           connectionEventListener;
 
     /**
      * Construct with parameters.
@@ -710,6 +711,7 @@ public ConnectionPool call() throws Exception {
                         syncCreateNumWhenNotWarmup);
                 } catch (Exception e) {
                     pool.removeAllAndTryClose();
+                    connTasks.remove(url.getUniqueKey());
                     throw e;
                 }
             }
@@ -914,7 +916,7 @@ public void setConnectionEventListener(ConnectionEventListener connectionEventLi
      *
      * @return property value of connPools
      */
-    public ConcurrentHashMap<String, RunStateRecordedFutureTask<ConnectionPool>> getConnPools() {
+    public ConcurrentMap<String, RunStateRecordedFutureTask<ConnectionPool>> getConnPools() {
         return this.connTasks;
     }
 }
diff --git a/src/main/java/com/alipay/remoting/connection/AbstractConnectionFactory.java b/src/main/java/com/alipay/remoting/connection/AbstractConnectionFactory.java
index f26e4c22..407a6b1f 100644
--- a/src/main/java/com/alipay/remoting/connection/AbstractConnectionFactory.java
+++ b/src/main/java/com/alipay/remoting/connection/AbstractConnectionFactory.java
@@ -31,6 +31,7 @@
 import com.alipay.remoting.config.BoltServerOption;
 import com.alipay.remoting.config.Configuration;
 import com.alipay.remoting.ExtendedNettyChannelHandler;
+import com.alipay.remoting.exception.RemotingException;
 import org.slf4j.Logger;
 
 import com.alipay.remoting.Connection;
@@ -189,6 +190,8 @@ public Connection createConnection(Url url) throws Exception {
             channel.pipeline().fireUserEventTriggered(ConnectionEventType.CONNECT);
         } else {
             channel.pipeline().fireUserEventTriggered(ConnectionEventType.CONNECT_FAILED);
+            throw new RemotingException("create connection, but channel is inactive, url is "
+                                        + url.getOriginUrl());
         }
         return conn;
     }
@@ -204,6 +207,9 @@ public Connection createConnection(String targetIP, int targetPort, int connectT
             channel.pipeline().fireUserEventTriggered(ConnectionEventType.CONNECT);
         } else {
             channel.pipeline().fireUserEventTriggered(ConnectionEventType.CONNECT_FAILED);
+            throw new RemotingException(
+                "create connection, but channel is inactive, target address is " + targetIP + ":"
+                        + targetPort);
         }
         return conn;
     }
@@ -219,6 +225,9 @@ public Connection createConnection(String targetIP, int targetPort, byte version
             channel.pipeline().fireUserEventTriggered(ConnectionEventType.CONNECT);
         } else {
             channel.pipeline().fireUserEventTriggered(ConnectionEventType.CONNECT_FAILED);
+            throw new RemotingException(
+                "create connection, but channel is inactive, target address is " + targetIP + ":"
+                        + targetPort);
         }
         return conn;
     }
diff --git a/src/main/java/com/alipay/remoting/util/ConcurrentHashSet.java b/src/main/java/com/alipay/remoting/util/ConcurrentHashSet.java
index efe39877..05bfe5d5 100644
--- a/src/main/java/com/alipay/remoting/util/ConcurrentHashSet.java
+++ b/src/main/java/com/alipay/remoting/util/ConcurrentHashSet.java
@@ -19,6 +19,7 @@
 import java.util.AbstractSet;
 import java.util.Iterator;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
 
 /**
  * Concurrent hash set.
@@ -27,7 +28,7 @@
  * @version $Id: ConcurrentHashSet.java, v 0.1 Mar 11, 2016 3:40:41 PM yunliang.shi Exp $
  */
 public class ConcurrentHashSet<E> extends AbstractSet<E> {
-    private ConcurrentHashMap<E, Boolean> map;
+    private ConcurrentMap<E, Boolean> map;
 
     /**
      * constructor