diff --git a/hardware/esp8266com/esp8266/libraries/ESP8266WiFi/src/include/ClientContext.h b/hardware/esp8266com/esp8266/libraries/ESP8266WiFi/src/include/ClientContext.h
index e80813013d..f9fd4e5245 100644
--- a/hardware/esp8266com/esp8266/libraries/ESP8266WiFi/src/include/ClientContext.h
+++ b/hardware/esp8266com/esp8266/libraries/ESP8266WiFi/src/include/ClientContext.h
@@ -169,6 +169,7 @@ class ClientContext {
 
             _size_sent = will_send;
             DEBUGV(":wr\r\n");
+            tcp_output( _pcb );
             _send_waiting = true;
             delay(5000); // max send timeout
             _send_waiting = false;