diff --git a/agent/ws/client.go b/agent/ws/client.go
index f1ab8c5..2a564ee 100644
--- a/agent/ws/client.go
+++ b/agent/ws/client.go
@@ -21,6 +21,7 @@ type Client struct {
 	
 	conn       *websocket.Conn
 	connMux    sync.RWMutex
+	writeMux   sync.Mutex
 	
 	reconnectInterval time.Duration
 	pingInterval      time.Duration
@@ -215,15 +216,18 @@ func (c *Client) runConnection() {
 			return
 			
 		case <-pingTicker.C:
+			c.writeMux.Lock()
 			c.connMux.RLock()
-			if c.conn != nil {
-				if err := c.conn.WriteMessage(websocket.PingMessage, nil); err != nil {
-					c.connMux.RUnlock()
+			conn := c.conn
+			c.connMux.RUnlock()
+			if conn != nil {
+				if err := conn.WriteMessage(websocket.PingMessage, nil); err != nil {
+					c.writeMux.Unlock()
 					log.Printf("Ping senden fehlgeschlagen: %v", err)
 					return
 				}
 			}
-			c.connMux.RUnlock()
+			c.writeMux.Unlock()
 			
 		case msg := <-msgChan:
 			go c.handleMessage(msg)
@@ -289,7 +293,10 @@ func (c *Client) SendMessage(msg Message) error {
 		return fmt.Errorf("keine WebSocket-Verbindung")
 	}
 	
-	return conn.WriteJSON(msg)
+	c.writeMux.Lock()
+	err := conn.WriteJSON(msg)
+	c.writeMux.Unlock()
+	return err
 }
 
 func (c *Client) SendBinaryData(data []byte) error {
@@ -301,7 +308,10 @@ func (c *Client) SendBinaryData(data []byte) error {
 		return fmt.Errorf("keine WebSocket-Verbindung")
 	}
 	
-	return conn.WriteMessage(websocket.BinaryMessage, data)
+	c.writeMux.Lock()
+	err := conn.WriteMessage(websocket.BinaryMessage, data)
+	c.writeMux.Unlock()
+	return err
 }
 
 func (c *Client) IsConnected() bool {