Primefaces push websockets issue using atmosphere

Question

I'm getting the below error in my chrome console .

webSocket connection to 'ws://tmsft.com.my/primepush/updateTicket?X-Atmosphere-tracking-id=0&X-Atmosphere-Framework=2.2.9-javascript&X-Atmosphere-Transport=websocket&X-Atmosphere-TrackMessageSize=true&X-atmo-protocol=true' failed: Error during WebSocket handshake: Unexpected response code: 501

push.js?ln=js&v=1.0:3221 Websocket closed, reason: Connection was closed abnormally (that is, with no close frame being sent).

push.js?ln=js&v=1.0:3221 Websocket closed, wasClean: false

push.js?ln=js&v=1.0:3221 Websocket failed. Downgrading to Comet and resending

I'm using Linux, Atmosphere, Primefaces 5.1 and JSF 2.2

Atmosphere dependency

    <dependency>
        <groupId>org.atmosphere</groupId>
        <artifactId>atmosphere-compat-tomcat</artifactId>
        <version>2.0.1</version>
    </dependency>
    <dependency>
        <groupId>org.atmosphere</groupId>
        <artifactId>atmosphere-runtime</artifactId>
        <version>2.2.5</version>
    </dependency>

Websocket Implementation :

    <dependency>
        <groupId>javax.websocket</groupId>
        <artifactId>javax.websocket-api</artifactId>
        <scope>provided</scope>
        <version>1.0</version>
    </dependency>

web.xml

    <servlet>
       <servlet-name>Push Servlet</servlet-name>
       <servlet-class>org.primefaces.push.PushServlet</servlet-class>
       <load-on-startup>1</load-on-startup>
       <async-supported>true</async-supported>
   </servlet>
  <servlet-mapping>
      <servlet-name>Push Servlet</servlet-name>
      <url-pattern>/primepush/*</url-pattern>
  </servlet-mapping>

How can I solve this issue?