ERR_SSL_PROTOCOL_ERROR

Hi All,

i want to using abap push notification.i am testing ECHO channel.But i get the this error: failed: Error in connection establishment: net::ERR_SSL_PROTOCOL_ERROR

can you help me please?

 this.oWs = new sap.ui.core.ws.SapPcpWebSocket("wss://<service>:8000/sap/bc/apc/sap/echo", sap.ui.core.ws.SapPcpWebSocket.SUPPORTED_PROTOCOLS.v10);