diff --git a/api/js/jsapi/egw_json.js b/api/js/jsapi/egw_json.js
index 823ae00e8d..f17062fe18 100644
--- a/api/js/jsapi/egw_json.js
+++ b/api/js/jsapi/egw_json.js
@@ -119,7 +119,7 @@ egw.extend('json', egw.MODULE_WND_LOCAL, function(_app, _wnd)
 				console.log("Server did not respond to ping in "+max_ping_response_time+" seconds --> try reconnecting");
 				check_timer = null;
 				this.openWebSocket(url, tokens, account_id, error, reconnect_time);
-			}, max_ping_response_time);
+			}.bind(this), max_ping_response_time);
 		}.bind(this);
 
 		this.websocket = new WebSocket(url);