diff --git a/app/providers/ProtocolProvider/protocol/protocol.ts b/app/providers/ProtocolProvider/protocol/protocol.ts
index a6ea06a..aa951f5 100644
--- a/app/providers/ProtocolProvider/protocol/protocol.ts
+++ b/app/providers/ProtocolProvider/protocol/protocol.ts
@@ -52,13 +52,13 @@ export default class Protocol extends EventEmitter {
                 _this.emit('handshake_complete');
                 _this.handshakeExchangeComplete = true;
                 _this._flushPacketQueue();
-                this.startHeartbeat(packet.getHeartbeatInterval());
+                _this.startHeartbeat(packet.getHeartbeatInterval());
             } 
             if(packet.getHandshakeState() == HandshakeState.NEED_DEVICE_VERIFICATION) {
                 console.info('[protocol] %chandshake exchange need device verification', 'color: orange;');
                 _this.emit('handshake_need_device_verification');
                 _this._packetQueue = [];
-                this.startHeartbeat(packet.getHeartbeatInterval());
+                _this.startHeartbeat(packet.getHeartbeatInterval());
             }
         });