Have you tried it with a lower strength key? Maybe use 2048 bit. This worked for me using Espruino Wifi. Maybe it is same issue. See this thread: http://forum.espruino.com/conversations/293351/#comment13233636
@Ollie 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.
Have you tried it with a lower strength key? Maybe use 2048 bit. This worked for me using Espruino Wifi. Maybe it is same issue. See this thread: http://forum.espruino.com/conversations/293351/#comment13233636