Do you have any other BLE devices that you can try to connect to, to see if the issue is specific to Puck.js?
@Gordon started
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
Do you have any other BLE devices that you can try to connect to, to see if the issue is specific to Puck.js?