Hi @jayloo, I was in the same troubles as you. Maybe you are helped with the solution that I found today at the Issue list for Openhabian
My summary of the problem would be: The WiFi of the RBP3B+ can become ‘soft blocked’, somehow. This is preventing normal operation of your wireless connection.
The solution is to unblock the wifi adapter with the following command:
sudo rfkill unblock wifi
You can check the status of your wifi adapter with:
rfkill list
Let me know if this was helping you too.