Q:

Can't use background task in Windows Phone 8.1 (the ID_CAP_NETWORKING required, but it's included in the manifest)

I need to update my Windows Phone application tile by downloading and parsing JSON. So I'm using Microsoft HTTP Client Libraries. 
And I've always got the exception Use of networking APIs requires the ID_CAP_NETWORKING capability to be defined in the application manifest when I'm trying to debug background task. 
But my manifest included ID_CAP_NETWORKING as required (screenshot https://fbcdn-sphotos-e-a.akamaihd.net/hphotos-ak-xaf1/t31.0-8/10750111_821340111262044_6461333323674658178_o.jpg).
I don't know what to do. I tried rebuild or recreate the app, but this didn't help. Also I can't find any documentation or an answer on the internet. 
Can you please write, what can I do to solve this problem?
This is demo project http://1drv.ms/1yjHm49 with reproduced problem (project's name is 'Meduza. Windows Phone').
I debug my application on Lumia 720 (if it can help).

A:

I re-downloaded your project and now I get your error.  So I thought, I must of done something before launching your project that fixed it.
It took me while, but I can get your project to work by doing this

Unzip project to directory
Open Project
Clean Project
Add Internet (Client and Server) in Package.appxmanifest file (make sure you save it before exiting)
Put the break points in your background task

And it works.  So a combination of Clean Build + editing the Package.appxmanifest did the trick for me.

