I Can't download Mortar Melon game from windows 8 store an encounter with the following error : Error Code : 0x80244018 I've a proxy server internet user . Can i get some help please ? i use a proxy based server to connect, internet explorer , mail, people etc. apps run fine (so i think my proxy settings in internet options is correct); but when i start downloading an app from store i get the Error Code : 0x80244018. even while downloading windows update i get the same error code.

You may not be able to download apps from store and few Windows updates if you are connected to Internet using proxy connection.

I would suggest you to try downloading the app by disabling proxy connection.
You may follow the steps to disable proxy connection.
If you are using any Proxy connection, then try disabling the proxy connection and check.
Follow the steps to disable proxy:
a. Click the Settings icon at the top right corner in internet explorer.
b. Click the Tools button, and then click Internet Options.
c. Click the Connections tab, and then click LAN settings.
d. Uncheck the box next to “proxy server for your LAN”.
e. Click on OK to save the setting and close window.
You may refer to the link for additional information.
Why can't I find or install an app from the Windows Store?
http://windows.microsoft.com/en-IN/windows-8/why-find-install-app-windows-store