diff --git a/sdk-core/src/main/java/io/milvus/client/MilvusServiceClient.java b/sdk-core/src/main/java/io/milvus/client/MilvusServiceClient.java
index 48f45aa43..11a331c05 100644
--- a/sdk-core/src/main/java/io/milvus/client/MilvusServiceClient.java
+++ b/sdk-core/src/main/java/io/milvus/client/MilvusServiceClient.java
@@ -184,17 +184,28 @@ public void start(ClientCall.Listener<RespT> responseListener, Metadata headers)
         }
 
         assert channel != null;
-        blockingStub = MilvusServiceGrpc.newBlockingStub(channel);
-        futureStub = MilvusServiceGrpc.newFutureStub(channel);
-
-        // calls a RPC Connect() to the remote server, and sends the client info to the server
-        // so that the server knows which client is interacting, especially for accesses log.
-        this.timeoutMs = connectParam.getConnectTimeoutMs(); // set this value to connectTimeoutMs to control the retry()
-        R<ConnectResponse> resp = this.retry(() -> connect(connectParam));
-        if (resp.getStatus() != R.Status.Success.getCode()) {
-            String msg = "Failed to initialize connection. Error: " + resp.getMessage();
-            logError(msg);
-            throw new RuntimeException(msg);
+
+        try {
+            blockingStub = MilvusServiceGrpc.newBlockingStub(channel);
+            futureStub = MilvusServiceGrpc.newFutureStub(channel);
+
+            // calls a RPC Connect() to the remote server, and sends the client info to the server
+            // so that the server knows which client is interacting, especially for accesses log.
+            this.timeoutMs = connectParam.getConnectTimeoutMs(); // set this value to connectTimeoutMs to control the retry()
+            R<ConnectResponse> resp = this.retry(() -> connect(connectParam));
+            if (resp.getStatus() != R.Status.Success.getCode()) {
+                String msg = "Failed to initialize connection. Error: " + resp.getMessage();
+                logError(msg);
+                throw new RuntimeException(msg);
+            }
+        } catch (Exception e) {
+            // close the channel if connect() throws exception, avoid leakage
+            try {
+                close(3);
+            } catch (InterruptedException ignored) {
+                Thread.currentThread().interrupt();
+            }
+            throw e;
         }
         this.timeoutMs = 0; // reset the timeout value to default
     }
diff --git a/sdk-core/src/main/java/io/milvus/v2/client/MilvusClientV2.java b/sdk-core/src/main/java/io/milvus/v2/client/MilvusClientV2.java
index 3f25d8404..64eee4086 100644
--- a/sdk-core/src/main/java/io/milvus/v2/client/MilvusClientV2.java
+++ b/sdk-core/src/main/java/io/milvus/v2/client/MilvusClientV2.java
@@ -136,16 +136,27 @@ private void connect(ConnectConfig connectConfig) {
                 close(3);
             }
         } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
             throw new RuntimeException(e);
         }
         channel = clientUtils.getChannel(connectConfig);
 
-        blockingStub = MilvusServiceGrpc.newBlockingStub(channel).withWaitForReady();
-        connect(connectConfig, blockingStub);
+        try {
+            blockingStub = MilvusServiceGrpc.newBlockingStub(channel).withWaitForReady();
+            connect(connectConfig, blockingStub);
 
-        if (connectConfig.getDbName() != null) {
-            // check if database exists
-            clientUtils.checkDatabaseExist(this.blockingStub, connectConfig.getDbName());
+            if (connectConfig.getDbName() != null) {
+                // check if database exists
+                clientUtils.checkDatabaseExist(this.blockingStub, connectConfig.getDbName());
+            }
+        } catch (Exception e) {
+            // close the channel if connect() and checkDatabaseExist() throws exception, avoid leakage
+            try {
+                close(3);
+            } catch (InterruptedException ignored) {
+                Thread.currentThread().interrupt();
+            }
+            throw e;
         }
     }