Openhab cannot control GPIO on raspberry pi

I had installed openhab2 using manual installation. i followed the instruction like the link says

and I also had installed MQTT server clients, GPIO binding, and HabCloud.

I edited the items (Type in sudo nano /etc/openhab2/items/home.items) and I type :
Switch LED “LED” { gpio=“pin:21” }
I also edited the sitemap (type in sudo nano /etc/openhab2/sitemaps/home.sitemap) and I type :
Switch item=LED

I can open my openhab and turn on/off the switch on its interface. but nothing happened my LED.

Anyone can help me?
p.s : I use debian jessie OS, and GPIO pin 21 BCM

Can you post your log when your action the switch the UI, please?

Please note that the GPIO pin in your items file is not the RasPi’s physical pin. GPIO 21 is exposed at pin 40 on the header according to the image at . Are you sure you have connected the right pin? Physical pin 21 is GPIO 9.