diff --git a/client.go b/client.go
index 751a5bde..a7da60a9 100644
--- a/client.go
+++ b/client.go
@@ -66,7 +66,7 @@ type Client struct {
 	responseChannels  *cache.Cache
 
 	lock       sync.RWMutex
-	closed     bool
+	isClosed   bool
 	conn       *websocket.Conn
 	node       *Node
 	sharedKeys map[string]*[sharedKeySize]byte
@@ -161,20 +161,28 @@ func (c *Client) Address() string {
 func (c *Client) IsClosed() bool {
 	c.lock.RLock()
 	defer c.lock.RUnlock()
-	return c.closed
+	return c.isClosed
 }
 
 // Close closes the client.
-func (c *Client) Close() {
+func (c *Client) Close() error {
 	c.lock.Lock()
 	defer c.lock.Unlock()
-	if !c.closed {
-		c.closed = true
-		close(c.OnConnect.C)
-		close(c.OnMessage.C)
-		close(c.reconnectChan)
-		c.conn.Close()
+
+	if c.isClosed {
+		return nil
 	}
+
+	c.isClosed = true
+
+	c.OnConnect.close()
+	c.OnMessage.close()
+
+	close(c.reconnectChan)
+
+	c.conn.Close()
+
+	return nil
 }
 
 // GetNode returns the node that client is currently connected to.
@@ -395,7 +403,7 @@ func (c *Client) handleMessage(msgType int, data []byte) error {
 
 			c.lock.RLock()
 			defer c.lock.RUnlock()
-			if c.closed {
+			if c.isClosed {
 				return nil
 			}
 
@@ -500,7 +508,7 @@ func (c *Client) handleMessage(msgType int, data []byte) error {
 
 			c.lock.RLock()
 			defer c.lock.RUnlock()
-			if c.closed {
+			if c.isClosed {
 				return nil
 			}
 
diff --git a/multiclient.go b/multiclient.go
index 503c45d1..6e628dbf 100644
--- a/multiclient.go
+++ b/multiclient.go
@@ -159,7 +159,14 @@ func NewMultiClient(account *Account, baseIdentifier string, numSubClients int,
 			if !ok {
 				return
 			}
+
+			m.lock.RLock()
+			if m.isClosed {
+				m.lock.RUnlock()
+				return
+			}
 			m.OnConnect.receive(node)
+			m.lock.RUnlock()
 
 			for {
 				select {
@@ -202,7 +209,14 @@ func NewMultiClient(account *Account, baseIdentifier string, numSubClients int,
 								return nil
 							}
 						}
+
+						m.lock.RLock()
+						if m.isClosed {
+							m.lock.RUnlock()
+							return
+						}
 						m.OnMessage.receive(msg, true)
+						m.lock.RUnlock()
 					}
 				case <-m.onClose:
 					return
@@ -679,12 +693,19 @@ func (m *MultiClient) Close() error {
 
 	time.AfterFunc(time.Duration(m.config.SessionConfig.Linger)*time.Millisecond, func() {
 		for _, client := range m.GetClients() {
-			client.Close()
+			err := client.Close()
+			if err != nil {
+				log.Println(err)
+				continue
+			}
 		}
 	})
 
 	m.isClosed = true
 
+	m.OnConnect.close()
+	m.OnMessage.close()
+
 	close(m.onClose)
 
 	return nil
diff --git a/util.go b/util.go
index 7b360835..a119b777 100644
--- a/util.go
+++ b/util.go
@@ -212,6 +212,10 @@ func (c *OnConnect) receive(node *Node) {
 	}
 }
 
+func (c *OnConnect) close() {
+	close(c.C)
+}
+
 // OnMessageFunc is a wrapper type for gomobile compatibility.
 type OnMessageFunc interface{ OnMessage(*Message) }
 
@@ -249,6 +253,10 @@ func (c *OnMessage) receive(msg *Message, verbose bool) {
 	}
 }
 
+func (c *OnMessage) close() {
+	close(c.C)
+}
+
 // OnErrorFunc is a wrapper type for gomobile compatibility.
 type OnErrorFunc interface{ OnError(error) }
 
@@ -284,6 +292,10 @@ func (c *OnError) receive(err error) {
 	}
 }
 
+func (c *OnError) close() {
+	close(c.C)
+}
+
 // ClientAddr represents NKN client address. It implements net.Addr interface.
 type ClientAddr struct {
 	addr string