Device doesn't reply

I assume from your posts that you've actually managed to connect just fine in the past, and something has changed?

• Could you try connecting with another device (your phone for instance?) to figure out whether the board is at fault.
  
• And could you also try restarting your computer? Sometimes your computer's Bluetooth stack can get confused (just disabling/enabling bluetooth may fix it, but a restart makes sure).
  
• Since you'd connected before it's possible that you had uploaded some code to the MDBT42Q that stopped it responding. See http://www.espruino.com/MDBT42Q#hard-res­et for how to start up the board without loading any saved code, which would return it to a state where you could connect just fine