Can't update Appium

Hi,
I’m trying to update Appium via NPM, but having some issues.
i’ll be glad to have some assistance.

here is the output:

C:\Users\x3686167>npm install -g appium
npm ERR! Windows_NT 6.1.7601
npm ERR! argv “C:\Program Files\nodejs\node.exe” “C:\Program Files\nodejs\
node_modules\npm\bin\npm-cli.js” “install” “-g” “appium”
npm ERR! node v4.4.7
npm ERR! npm v2.15.8
npm ERR! code ETIMEDOUT
npm ERR! errno ETIMEDOUT
npm ERR! syscall connect

npm ERR! network connect ETIMEDOUT 151.101.16.162:443
npm ERR! network This is most likely not a problem with npm itself
npm ERR! network and is related to network connectivity.
npm ERR! network In most cases you are behind a proxy or have bad network settin
gs.
npm ERR! network
npm ERR! network If you are behind a proxy, please make sure that the
npm ERR! network ‘proxy’ config is set properly. See: ‘npm help config’

npm ERR! Please include the following file with any support request:
npm ERR! C:\Users\x3686167\npm-debug.log

Thanks.