Installing mosquitto on OpenWrt and not working......

Hi Folks,

I have set up mosquitto on an arduino YUN; downloaded the openwrt version. I am trying to use an ESP8266 device to connect to this. The ESP device will connect normally to another external broker (including mosquitto test), but on the mosquitto version for openwrt

I get this error message.

1477929323: New connection from 192.168.29.39.
1477929323: Invalid protocol "MQTT" in CONNECT from 192.168.29.39.
1477929323: Socket read error on client (null), disconnecting.

Does anyone know whay this is happening?
Regards
Phil