Puck js, how to send MQTT message with button pressed?

Ahh I just Googled the message and found this:

Some BLE adapters like Sena UD-100 (Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)) cannot connect to a peripheral while they are scanning. You will get the following message when trying to connect :
Error: Command disallowed
You need to stop scanning before trying to connect in order to solve this issue.

So it looks like it's something funny with your Bluetooth dongle

I've just updated EspruinoHub - please could you git pull it and see if that helps things?